[crankshaft] Remove the useless HAllocateBlockContext instruction.

src/crankshaft/ppc/lithium-codegen-ppc.cc

Index: src/crankshaft/ppc/lithium-codegen-ppc.cc
diff --git a/src/crankshaft/ppc/lithium-codegen-ppc.cc b/src/crankshaft/ppc/lithium-codegen-ppc.cc
index 387218f3fca91abafcf38ef94a32362301280fc9..550209d970c8e9916f8bc2f6251330d0bcec901a 100644
--- a/src/crankshaft/ppc/lithium-codegen-ppc.cc
+++ b/src/crankshaft/ppc/lithium-codegen-ppc.cc
@@ -5755,15 +5755,6 @@ void LCodeGen::DoStoreFrameContext(LStoreFrameContext* instr) {
 }
 
 
-void LCodeGen::DoAllocateBlockContext(LAllocateBlockContext* instr) {
-  Handle<ScopeInfo> scope_info = instr->scope_info();
-  __ Push(scope_info);
-  __ push(ToRegister(instr->function()));
-  CallRuntime(Runtime::kPushBlockContext, instr);
-  RecordSafepoint(Safepoint::kNoLazyDeopt);
-}
-
-
 #undef __
 }  // namespace internal
 }  // namespace v8