Simple fixes

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index 7f293d10fc99234ecdfe59c14a3cf7fedeaf007a..6f888a858b9e5f00326787b60c834e3515bfb3c8 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -3057,7 +3057,8 @@ RawError* Class::EnsureIsFinalized(Thread* thread) const {
     return Error::null();
   }
   if (Compiler::IsBackgroundCompilation()) {
-    Compiler::AbortBackgroundCompilation(Thread::kNoDeoptId);
+    Compiler::AbortBackgroundCompilation(Thread::kNoDeoptId,
+        "Class finalization while compiling");
   }
   ASSERT(thread->IsMutatorThread());
   ASSERT(thread != NULL);