[crankshaft] Get rid of the StoreFrameContext instruction.

src/crankshaft/x64/lithium-x64.cc

Index: src/crankshaft/x64/lithium-x64.cc
diff --git a/src/crankshaft/x64/lithium-x64.cc b/src/crankshaft/x64/lithium-x64.cc
index 89ee91ff2b96dae0c455fb05e0c76cd42ec0c826..b06e52107d36ed285b71064f79e9d562aa1d0328 100644
--- a/src/crankshaft/x64/lithium-x64.cc
+++ b/src/crankshaft/x64/lithium-x64.cc
@@ -2628,13 +2628,6 @@ LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   return AssignPointerMap(result);
 }
 
-
-LInstruction* LChunkBuilder::DoStoreFrameContext(HStoreFrameContext* instr) {
-  LOperand* context = UseRegisterAtStart(instr->context());
-  return new(zone()) LStoreFrameContext(context);
-}
-
-
 }  // namespace internal
 }  // namespace v8