[crankshaft] Remove the useless HAllocateBlockContext instruction.

src/crankshaft/mips64/lithium-mips64.cc

Index: src/crankshaft/mips64/lithium-mips64.cc
diff --git a/src/crankshaft/mips64/lithium-mips64.cc b/src/crankshaft/mips64/lithium-mips64.cc
index d24797ea51bc14496acb837ec0eeb474bff0a68b..d35d8c75fb82c1427e286c1a0b784b2ac5eb6969 100644
--- a/src/crankshaft/mips64/lithium-mips64.cc
+++ b/src/crankshaft/mips64/lithium-mips64.cc
@@ -2554,16 +2554,6 @@ LInstruction* LChunkBuilder::DoStoreFrameContext(HStoreFrameContext* instr) {
 }
 
 
-LInstruction* LChunkBuilder::DoAllocateBlockContext(
-    HAllocateBlockContext* instr) {
-  LOperand* context = UseFixed(instr->context(), cp);
-  LOperand* function = UseRegisterAtStart(instr->function());
-  LAllocateBlockContext* result =
-      new(zone()) LAllocateBlockContext(context, function);
-  return MarkAsCall(DefineFixed(result, cp), instr);
-}
-
-
 }  // namespace internal
 }  // namespace v8