[crankshaft] Get rid of the StoreFrameContext instruction.

src/crankshaft/ppc/lithium-ppc.cc

Index: src/crankshaft/ppc/lithium-ppc.cc
diff --git a/src/crankshaft/ppc/lithium-ppc.cc b/src/crankshaft/ppc/lithium-ppc.cc
index 16c25855d2c509a7d6459a191b1f80f2f4febc60..0dbe7309e7d08fc253fab9eedc221a66bc3c7076 100644
--- a/src/crankshaft/ppc/lithium-ppc.cc
+++ b/src/crankshaft/ppc/lithium-ppc.cc
@@ -2517,11 +2517,5 @@ 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