[stubs] Ensure that the stubs are recompiled in respective tests.

src/code-stubs.cc

Index: src/code-stubs.cc
diff --git a/src/code-stubs.cc b/src/code-stubs.cc
index 54d5f775acc5926426801a9c2e223ec2d494aff2..43d88edbbc551c5075302f861b337adeff0088b7 100644
--- a/src/code-stubs.cc
+++ b/src/code-stubs.cc
@@ -112,6 +112,12 @@ Handle<Code> CodeStub::GetCodeCopy(const Code::FindAndReplacePattern& pattern) {
   return ic;
 }
 
+void CodeStub::DeleteStubFromCacheForTesting() {
+  Heap* heap = isolate_->heap();
+  Handle<UnseededNumberDictionary> dict(heap->code_stubs());
+  dict = UnseededNumberDictionary::DeleteKey(dict, GetKey());
+  heap->SetRootCodeStubs(*dict);
+}
 
 Handle<Code> PlatformCodeStub::GenerateCode() {
   Factory* factory = isolate()->factory();