Get rid of the HInstanceSize instruction.

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index 3662d21c04772572c30f9f428cb2e685626c1ee7..7e9e3623199be4dd4634fd294a094f309e184bad 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -2996,14 +2996,6 @@ void LCodeGen::DoDeferredInstanceOfKnownGlobal(LInstanceOfKnownGlobal* instr,
 }
 
 
-void LCodeGen::DoInstanceSize(LInstanceSize* instr) {
-  Register object = ToRegister(instr->object());
-  Register result = ToRegister(instr->result());
-  __ mov(result, FieldOperand(object, HeapObject::kMapOffset));
-  __ movzx_b(result, FieldOperand(result, Map::kInstanceSizeOffset));
-}
-
-
 void LCodeGen::DoCmpT(LCmpT* instr) {
   Token::Value op = instr->op();