[crankshaft] Remove the useless HMapEnumLength instruction.

src/crankshaft/ia32/lithium-codegen-ia32.cc

Index: src/crankshaft/ia32/lithium-codegen-ia32.cc
diff --git a/src/crankshaft/ia32/lithium-codegen-ia32.cc b/src/crankshaft/ia32/lithium-codegen-ia32.cc
index 4777a85fae226177dcb1b9c5e3416875f12a9f87..cc3fc90a2ef7b09262a99c6fa355662cede201f5 100644
--- a/src/crankshaft/ia32/lithium-codegen-ia32.cc
+++ b/src/crankshaft/ia32/lithium-codegen-ia32.cc
@@ -1668,13 +1668,6 @@ void LCodeGen::DoConstantT(LConstantT* instr) {
 }
 
 
-void LCodeGen::DoMapEnumLength(LMapEnumLength* instr) {
-  Register result = ToRegister(instr->result());
-  Register map = ToRegister(instr->value());
-  __ EnumLength(result, map);
-}
-
-
 Operand LCodeGen::BuildSeqStringOperand(Register string,
                                         LOperand* index,
                                         String::Encoding encoding) {