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

src/x64/ic-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1310 matching lines @@
 
 void LoadIC::GenerateMegamorphic(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax    : receiver
   //  -- rcx    : name
   //  -- rsp[0] : return address
   // -----------------------------------
 
   // Probe the stub cache.
   Code::Flags flags = Code::ComputeFlags(
-      Code::LOAD_IC, MONOMORPHIC, Code::HANDLER_FRAGMENT);
+      Code::STUB, MONOMORPHIC, Code::kNoExtraICState,
+      Code::NORMAL, Code::LOAD_IC);
   Isolate::Current()->stub_cache()->GenerateProbe(
       masm, flags, rax, rcx, rbx, rdx);
 
   // Cache miss: Jump to runtime.
   StubCompiler::GenerateLoadMiss(masm, Code::LOAD_IC);
 }
 
 
 void LoadIC::GenerateNormal(MacroAssembler* masm) {
   // ----------- S t a t e -------------
@@ skipping 345 matching lines @@
   Condition cc = (check == ENABLE_INLINED_SMI_CHECK)
       ? (*jmp_address == Assembler::kJncShortOpcode ? not_zero : zero)
       : (*jmp_address == Assembler::kJnzShortOpcode ? not_carry : carry);
   *jmp_address = static_cast<byte>(Assembler::kJccShortPrefix | cc);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64