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

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 7278c95e92b30bd572f177a5fb195229af4b98dd..2cc6e37ea9c16905ed19882f30485376bd6a3fe8 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -2372,14 +2372,6 @@ void LCodeGen::DoCmpObjectEqAndBranch(LCmpObjectEqAndBranch* instr) {
 }
 
 
-void LCodeGen::DoCmpConstantEqAndBranch(LCmpConstantEqAndBranch* instr) {
-  Register left = ToRegister(instr->left());
-
-  __ cmp(left, Operand(instr->hydrogen()->right()));
-  EmitBranch(instr, eq);
-}
-
-
 Condition LCodeGen::EmitIsObject(Register input,
                                  Register temp1,
                                  Label* is_not_object,