Work around for bug 4995 to unbreak VM build.

dart/runtime/lib/errors_patch.dart

Index: dart/runtime/lib/errors_patch.dart
diff --git a/dart/runtime/lib/errors_patch.dart b/dart/runtime/lib/errors_patch.dart
index c118932ae6e3c15d2611c5cd0c2bc7ebca30e4ab..5547e584aabe7c33f8d5fa497607f39f9c93315d 100644
--- a/dart/runtime/lib/errors_patch.dart
+++ b/dart/runtime/lib/errors_patch.dart
@@ -8,7 +8,9 @@ patch class NoSuchMethodError {
       return object.toString();
     }
     if (object is String) {
-      String escaped = object.replaceAll('"', '\\"');
+      // TODO(ahe): Remove hack when http://dartbug.com/4995 is fixed.
+      const hack = '\\' '"';
+      String escaped = object.replaceAll('"',  hack);
       return '"$escaped"';
     }
     return Object._toString(object);