Remove the unused HElementsKind instruction.

src/arm/lithium-arm.cc

Index: src/arm/lithium-arm.cc
diff --git a/src/arm/lithium-arm.cc b/src/arm/lithium-arm.cc
index 3885b6b6967526d111d3aa212b3bd3a4be8cfd60..8b3758e1ddbc6b907dfe232dc8a286b0f1926630 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -1705,12 +1705,6 @@ LInstruction* LChunkBuilder::DoMapEnumLength(HMapEnumLength* instr) {
 }
 
 
-LInstruction* LChunkBuilder::DoElementsKind(HElementsKind* instr) {
-  LOperand* object = UseRegisterAtStart(instr->value());
-  return DefineAsRegister(new(zone()) LElementsKind(object));
-}
-
-
 LInstruction* LChunkBuilder::DoValueOf(HValueOf* instr) {
   LOperand* object = UseRegister(instr->value());
   LValueOf* result = new(zone()) LValueOf(object, TempRegister());