[crankshaft] Remove the useless HMapEnumLength instruction.

src/crankshaft/ppc/lithium-ppc.h

Index: src/crankshaft/ppc/lithium-ppc.h
diff --git a/src/crankshaft/ppc/lithium-ppc.h b/src/crankshaft/ppc/lithium-ppc.h
index e86edc9afc93d1d846e28bbc7174adb406e9c2a0..192e328042e20d521bc3ca5709da140fadbb154d 100644
--- a/src/crankshaft/ppc/lithium-ppc.h
+++ b/src/crankshaft/ppc/lithium-ppc.h
@@ -101,7 +101,6 @@ class LCodeGen;
   V(LoadKeyedGeneric)                        \
   V(LoadNamedField)                          \
   V(LoadNamedGeneric)                        \
-  V(MapEnumLength)                           \
   V(MathAbs)                                 \
   V(MathClz32)                               \
   V(MathExp)                                 \
@@ -1314,16 +1313,6 @@ class LCmpMapAndBranch final : public LControlInstruction<1, 1> {
 };
 
 
-class LMapEnumLength final : public LTemplateInstruction<1, 1, 0> {
- public:
-  explicit LMapEnumLength(LOperand* value) { inputs_[0] = value; }
-
-  LOperand* value() { return inputs_[0]; }
-
-  DECLARE_CONCRETE_INSTRUCTION(MapEnumLength, "map-enum-length")
-};
-
-
 class LSeqStringGetChar final : public LTemplateInstruction<1, 2, 0> {
  public:
   LSeqStringGetChar(LOperand* string, LOperand* index) {