Add functionality to get full stack trace when exceptions are thrown.

sdk/lib/_internal/compiler/implementation/lib/core_patch.dart

Index: sdk/lib/_internal/compiler/implementation/lib/core_patch.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/lib/core_patch.dart	(revision 19105)
+++ sdk/lib/_internal/compiler/implementation/lib/core_patch.dart	(working copy)
@@ -286,3 +286,13 @@
   }
 }
 
+patch class StackTrace {
+  patch String get fullStackTrace {
+    throw new UnsupportedError('fullStackTrace');
+  }
+
+  patch String get stackTrace {
+    throw new UnsupportedError('stackTrace');
+  }
+}
+