Compile FastCloneShallowObjectStub using Crankshaft.

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 57de0c8e17e3c6aeae89c220990a29fb690815a8..1075b2ed0ea52f255ea3cd01873db76f12c74fb3 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -979,6 +979,12 @@ LInstruction* LChunkBuilder::DoInstanceOfKnownGlobal(
 }
 
 
+LInstruction* LChunkBuilder::DoInstanceSize(HInstanceSize* instr) {
+  LOperand* object = UseRegisterAtStart(instr->object());
+  return DefineAsRegister(new(zone()) LInstanceSize(object));
+}
+
+
 LInstruction* LChunkBuilder::DoWrapReceiver(HWrapReceiver* instr) {
   LOperand* receiver = UseRegister(instr->receiver());
   LOperand* function = UseRegisterAtStart(instr->function());