Make IC patching resilient to flushing of the original target() ic.

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 62b7af224f5b3c72cabf2a0fd3533b0f624340fd..9c8225ea459d449fa6809a13253425671e3af984 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -251,6 +251,7 @@ class PlatformCodeStub : public CodeStub {
   virtual Handle<Code> GenerateCode();
 
   virtual int GetCodeKind() { return Code::STUB; }
+  virtual int GetStubFlags() { return -1; }
 
  protected:
   // Generates the assembler code for the stub.
@@ -662,11 +663,8 @@ class StoreArrayLengthStub: public StoreICStub {
 class HandlerStub: public ICStub {
  public:
   explicit HandlerStub(Code::Kind kind) : ICStub(kind) { }
-
- protected:
-  virtual Code::ExtraICState GetExtraICState() {
-    return Code::HANDLER_FRAGMENT;
-  }
+  virtual int GetCodeKind() { return Code::STUB; }
+  virtual int GetStubFlags() { return kind(); }
 };