core: minor fix for the log wrapper with debug purpose (#30454)

After this PR, https://github.com/ethereum/go-ethereum/pull/28187, the
way to set the default logger is different. This PR only updates the way
to set logger in some test cases' comments that existed in the codebase
(since this commit
https://github.com/ethereum/go-ethereum/commit/b63e3c37a6). Although I
am not sure if it a good way to leave the code in the comment, it truly
makes me more efficiently to debug and fix the failing test cases.

core/blockchain_repair_test.go

@@ -1757,8 +1757,8 @@ func testRepair(t *testing.T, tt *rewindTest, snapshots bool) {
 
 func testRepairWithScheme(t *testing.T, tt *rewindTest, snapshots bool, scheme string) {
 	// It's hard to follow the test case, visualize the input
-	// log.Root().SetHandler(log.LvlFilterHandler(log.LvlTrace, log.StreamHandler(os.Stderr, log.TerminalFormat(true))))
-	// fmt.Println(tt.dump(true))
+	// log.SetDefault(log.NewLogger(log.NewTerminalHandlerWithLevel(os.Stderr, log.LevelInfo, true)))
+	// fmt.Println(tt.dump(false))
 
 	// Create a temporary persistent database
 	datadir := t.TempDir()
@@ -1908,7 +1908,7 @@ func TestIssue23496(t *testing.T) {
 
 func testIssue23496(t *testing.T, scheme string) {
 	// It's hard to follow the test case, visualize the input
-	//log.Root().SetHandler(log.LvlFilterHandler(log.LvlTrace, log.StreamHandler(os.Stderr, log.TerminalFormat(true))))
+	// log.SetDefault(log.NewLogger(log.NewTerminalHandlerWithLevel(os.Stderr, log.LevelInfo, true)))
 
 	// Create a temporary persistent database
 	datadir := t.TempDir()

core/blockchain_sethead_test.go

@@ -1961,7 +1961,7 @@ func testSetHead(t *testing.T, tt *rewindTest, snapshots bool) {
 
 func testSetHeadWithScheme(t *testing.T, tt *rewindTest, snapshots bool, scheme string) {
 	// It's hard to follow the test case, visualize the input
-	// log.Root().SetHandler(log.LvlFilterHandler(log.LvlTrace, log.StreamHandler(os.Stderr, log.TerminalFormat(true))))
+	// log.SetDefault(log.NewLogger(log.NewTerminalHandlerWithLevel(os.Stderr, log.LevelInfo, true)))
 	// fmt.Println(tt.dump(false))
 
 	// Create a temporary persistent database

core/blockchain_snapshot_test.go

@@ -222,8 +222,8 @@ type snapshotTest struct {
 
 func (snaptest *snapshotTest) test(t *testing.T) {
 	// It's hard to follow the test case, visualize the input
-	// log.Root().SetHandler(log.LvlFilterHandler(log.LvlTrace, log.StreamHandler(os.Stderr, log.TerminalFormat(true))))
-	// fmt.Println(tt.dump())
+	// log.SetDefault(log.NewLogger(log.NewTerminalHandlerWithLevel(os.Stderr, log.LevelInfo, true)))
+	// fmt.Println(snaptest.dump())
 	chain, blocks := snaptest.prepare(t)
 
 	// Restart the chain normally
@@ -245,8 +245,8 @@ type crashSnapshotTest struct {
 
 func (snaptest *crashSnapshotTest) test(t *testing.T) {
 	// It's hard to follow the test case, visualize the input
-	// log.Root().SetHandler(log.LvlFilterHandler(log.LvlTrace, log.StreamHandler(os.Stderr, log.TerminalFormat(true))))
-	// fmt.Println(tt.dump())
+	// log.SetDefault(log.NewLogger(log.NewTerminalHandlerWithLevel(os.Stderr, log.LevelInfo, true)))
+	// fmt.Println(snaptest.dump())
 	chain, blocks := snaptest.prepare(t)
 
 	// Pull the plug on the database, simulating a hard crash
@@ -297,8 +297,8 @@ type gappedSnapshotTest struct {
 
 func (snaptest *gappedSnapshotTest) test(t *testing.T) {
 	// It's hard to follow the test case, visualize the input
-	// log.Root().SetHandler(log.LvlFilterHandler(log.LvlTrace, log.StreamHandler(os.Stderr, log.TerminalFormat(true))))
-	// fmt.Println(tt.dump())
+	// log.SetDefault(log.NewLogger(log.NewTerminalHandlerWithLevel(os.Stderr, log.LevelInfo, true)))
+	// fmt.Println(snaptest.dump())
 	chain, blocks := snaptest.prepare(t)
 
 	// Insert blocks without enabling snapshot if gapping is required.
@@ -341,8 +341,8 @@ type setHeadSnapshotTest struct {
 
 func (snaptest *setHeadSnapshotTest) test(t *testing.T) {
 	// It's hard to follow the test case, visualize the input
-	// log.Root().SetHandler(log.LvlFilterHandler(log.LvlTrace, log.StreamHandler(os.Stderr, log.TerminalFormat(true))))
-	// fmt.Println(tt.dump())
+	// log.SetDefault(log.NewLogger(log.NewTerminalHandlerWithLevel(os.Stderr, log.LevelInfo, true)))
+	// fmt.Println(snaptest.dump())
 	chain, blocks := snaptest.prepare(t)
 
 	// Rewind the chain if setHead operation is required.
@@ -370,8 +370,8 @@ type wipeCrashSnapshotTest struct {
 
 func (snaptest *wipeCrashSnapshotTest) test(t *testing.T) {
 	// It's hard to follow the test case, visualize the input
-	// log.Root().SetHandler(log.LvlFilterHandler(log.LvlTrace, log.StreamHandler(os.Stderr, log.TerminalFormat(true))))
-	// fmt.Println(tt.dump())
+	// log.SetDefault(log.NewLogger(log.NewTerminalHandlerWithLevel(os.Stderr, log.LevelInfo, true)))
+	// fmt.Println(snaptest.dump())
 	chain, blocks := snaptest.prepare(t)
 
 	// Firstly, stop the chain properly, with all snapshot journal

core/blockchain_test.go

@@ -2126,9 +2126,9 @@ func testSideImport(t *testing.T, numCanonBlocksInSidechain, blocksBetweenCommon
 //	[ Cn, Cn+1, Cc, Sn+3 ... Sm]
 //	^    ^    ^  pruned
 func TestPrunedImportSide(t *testing.T) {
-	//glogger := log.NewGlogHandler(log.StreamHandler(os.Stdout, log.TerminalFormat(false)))
-	//glogger.Verbosity(3)
-	//log.Root().SetHandler(log.Handler(glogger))
+	// glogger := log.NewGlogHandler(log.NewTerminalHandler(os.Stderr, false))
+	// glogger.Verbosity(3)
+	// log.SetDefault(log.NewLogger(glogger))
 	testSideImport(t, 3, 3, -1)
 	testSideImport(t, 3, -3, -1)
 	testSideImport(t, 10, 0, -1)
@@ -2137,9 +2137,9 @@ func TestPrunedImportSide(t *testing.T) {
 }
 
 func TestPrunedImportSideWithMerging(t *testing.T) {
-	//glogger := log.NewGlogHandler(log.StreamHandler(os.Stdout, log.TerminalFormat(false)))
-	//glogger.Verbosity(3)
-	//log.Root().SetHandler(log.Handler(glogger))
+	// glogger := log.NewGlogHandler(log.NewTerminalHandler(os.Stderr, false))
+	// glogger.Verbosity(3)
+	// log.SetDefault(log.NewLogger(glogger))
 	testSideImport(t, 3, 3, 0)
 	testSideImport(t, 3, -3, 0)
 	testSideImport(t, 10, 0, 0)
@@ -3629,7 +3629,7 @@ func TestSetCanonical(t *testing.T) {
 }
 
 func testSetCanonical(t *testing.T, scheme string) {
-	//log.Root().SetHandler(log.LvlFilterHandler(log.LvlDebug, log.StreamHandler(os.Stderr, log.TerminalFormat(true))))
+	// log.SetDefault(log.NewLogger(log.NewTerminalHandlerWithLevel(os.Stderr, log.LevelInfo, true)))
 
 	var (
 		key, _  = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")