build: raise test timeout back to 10 mins (#21027)

build/ci.go

@@ -325,7 +325,7 @@ func doTest(cmdline []string) {
 	// Test a single package at a time. CI builders are slow
 	// and some tests run into timeouts under load.
 	gotest := goTool("test", buildFlags(env)...)
-	gotest.Args = append(gotest.Args, "-p", "1", "-timeout", "5m")
+	gotest.Args = append(gotest.Args, "-p", "1")
 	if *coverage {
 		gotest.Args = append(gotest.Args, "-covermode=atomic", "-cover")
 	}