dart2js cps: Stack trace should be obtained from raw exception value.

pkg/compiler/lib/src/js_backend/codegen/unsugar.dart

 library dart2js.unsugar_cps;
 
 import '../../cps_ir/cps_ir_nodes.dart';
 
 // TODO(karlklose): share the [ParentVisitor].
 import '../../cps_ir/optimizers.dart';
 import '../../constants/expressions.dart';
 import '../../constants/values.dart';
 import '../../elements/elements.dart' show
     ClassElement,
@@ skipping 175 matching lines @@
     if (_exceptionParameter.hasAtLeastOneUse ||
         stackTraceParameter.hasAtLeastOneUse) {
       Parameter exceptionValue = new Parameter(null);
       exceptionValue.substituteFor(_exceptionParameter);
       insertStaticCall(_glue.getExceptionUnwrapper(), [_exceptionParameter],
           exceptionValue, body);
 
       if (stackTraceParameter.hasAtLeastOneUse) {
         Parameter stackTraceValue = new Parameter(null);
         stackTraceValue.substituteFor(stackTraceParameter);
-        insertStaticCall(_glue.getTraceFromException(), [exceptionValue],
+        insertStaticCall(_glue.getTraceFromException(), [_exceptionParameter],
             stackTraceValue, body);
       }
     }
 
     assert(stackTraceParameter.hasNoUses);
     node.handler.parameters.removeLast();
   }
 
   @override
   visitLetHandler(LetHandler node) {
@@ skipping 79 matching lines @@
         new LetPrim(i,
             new Branch(new IsTrue(i),
                 node.trueContinuation.definition,
                 node.falseContinuation.definition)));
     condition.value.unlink();
     node.trueContinuation.unlink();
     node.falseContinuation.unlink();
     parent.body = newNode;
   }
 }