Remove HCompareConstantEqAndBranch (never used), and its corresponding Lithium instructions.

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 b98b462386750a60a2c85660e5b9de94e1738831..ea53d91be384f697dc604e4891e036e4dd3f2339 100644
--- a/src/arm/lithium-arm.cc
+++ b/src/arm/lithium-arm.cc
@@ -1731,13 +1731,6 @@ LInstruction* LChunkBuilder::DoCompareObjectEqAndBranch(
 }
 
 
-LInstruction* LChunkBuilder::DoCompareConstantEqAndBranch(
-    HCompareConstantEqAndBranch* instr) {
-  LOperand* value = UseRegisterAtStart(instr->value());
-  return new(zone()) LCmpConstantEqAndBranch(value);
-}
-
-
 LInstruction* LChunkBuilder::DoIsObjectAndBranch(HIsObjectAndBranch* instr) {
   ASSERT(instr->value()->representation().IsTagged());
   LOperand* value = UseRegisterAtStart(instr->value());