[crankshaft] Remove the useless HAllocateBlockContext instruction.

src/crankshaft/mips/lithium-mips.cc

Index: src/crankshaft/mips/lithium-mips.cc
diff --git a/src/crankshaft/mips/lithium-mips.cc b/src/crankshaft/mips/lithium-mips.cc
index ef9da821d6a119c9ca27b38ded0b35e87d0cf147..ebe2d2b2a8f7eb40ebc21ede52c2469c0bfcd5c2 100644
--- a/src/crankshaft/mips/lithium-mips.cc
+++ b/src/crankshaft/mips/lithium-mips.cc
@@ -2549,16 +2549,6 @@ LInstruction* LChunkBuilder::DoStoreFrameContext(HStoreFrameContext* instr) {
   return new(zone()) LStoreFrameContext(context);
 }
 
-
-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