Fix some out-of-line constant pool garbage collection bugs.

src/x64/frames-x64.cc

 // Copyright 2010 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
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@@ skipping 36 matching lines @@
 
 
 Register StubFailureTrampolineFrame::fp_register() { return rbp; }
 Register StubFailureTrampolineFrame::context_register() { return rsi; }
 Register StubFailureTrampolineFrame::constant_pool_pointer_register() {
   UNREACHABLE();
   return no_reg;
 }
 
 
+Object*& ExitFrame::constant_pool_slot() const {
+  UNREACHABLE();
+  return Memory::Object_at(NULL);
+}
+
+
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64