Improve internal compiler API so that OSR code is never installed on function.

runtime/vm/unit_test.cc

Index: runtime/vm/unit_test.cc
diff --git a/runtime/vm/unit_test.cc b/runtime/vm/unit_test.cc
index b8440679ae727031e13430111092c7e673867c15..147d0eb73afce0358c8f37b00e447133a44d2de2 100644
--- a/runtime/vm/unit_test.cc
+++ b/runtime/vm/unit_test.cc
@@ -472,9 +472,9 @@ bool CompilerTest::TestCompileFunction(const Function& function) {
   Thread* thread = Thread::Current();
   ASSERT(thread != NULL);
   ASSERT(ClassFinalizer::AllClassesFinalized());
-  const Error& error =
-      Error::Handle(Compiler::CompileFunction(thread, function));
-  return error.IsNull();
+  const Object& result =
+      Object::Handle(Compiler::CompileFunction(thread, function));
+  return result.IsCode();
 }