refactor getSourceLocationFromVMTraceIndex to a promise

libs/remix-debug/src/solidity-decoder/internalCallTree.js

@@ -126,8 +126,8 @@ class InternalCallTree {
 
   extractSourceLocation (step) {
     return new Promise((resolve, reject) => {
-      try {
-        const address = this.traceManager.getCurrentCalledAddressAt(step)
+      this.traceManager.getCurrentCalledAddressAt(step, (error, address) => {
+        if (!error) {
           try {
             this.sourceLocationTracker.getSourceLocationFromVMTraceIndex(address, step, this.solidityProxy.contracts).then(resolve).catch((error) => {
               return reject('InternalCallTree - Cannot retrieve sourcelocation for step ' + step + ' ' + error)
@@ -135,10 +135,11 @@ class InternalCallTree {
           } catch (error) {
             return reject('InternalCallTree - Cannot retrieve address for step ' + step + ' ' + error)
           }
-      } catch (error) {
+        } else {
           return reject('InternalCallTree - Cannot retrieve address for step ' + step + ' ' + error)
         }
       })
+    })
   }
 
 }