[GC] Fix code flushing to use bytecode if it exists.

test/cctest/heap/test-heap.cc

Index: test/cctest/heap/test-heap.cc
diff --git a/test/cctest/heap/test-heap.cc b/test/cctest/heap/test-heap.cc
index ed7e667776e2699d5c732958035e514180eaeb03..73770a7e3b438edc125fc590804f7589d4ba0dd4 100644
--- a/test/cctest/heap/test-heap.cc
+++ b/test/cctest/heap/test-heap.cc
@@ -6275,9 +6275,9 @@ static void RemoveCodeAndGC(const v8::FunctionCallbackInfo<v8::Value>& args) {
   Isolate* isolate = CcTest::i_isolate();
   Handle<Object> obj = v8::Utils::OpenHandle(*args[0]);
   Handle<JSFunction> fun = Handle<JSFunction>::cast(obj);
+  fun->shared()->ClearBytecodeArray();  // Bytecode is code too.
   fun->ReplaceCode(*isolate->builtins()->CompileLazy());
   fun->shared()->ReplaceCode(*isolate->builtins()->CompileLazy());
-  fun->shared()->ClearBytecodeArray();  // Bytecode is code too.
   CcTest::CollectAllAvailableGarbage();
 }