Remove HCheckSmi, LCheckSmi and rename LCheckSmiAndReturn to LCheckSmi.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index dcfd7ab09cba8ad22e154591f87807b8fcc1ad91..f9b6e817af594436875be9e8e99e08379befc1d6 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -4903,13 +4903,6 @@ void LCodeGen::DoDoubleToSmi(LDoubleToSmi* instr) {
 }
 
 
-void LCodeGen::DoCheckSmiAndReturn(LCheckSmiAndReturn* instr) {
-  LOperand* input = instr->value();
-  Condition cc = masm()->CheckSmi(ToRegister(input));
-  DeoptimizeIf(NegateCondition(cc), instr->environment());
-}
-
-
 void LCodeGen::DoCheckSmi(LCheckSmi* instr) {
   LOperand* input = instr->value();
   Condition cc = masm()->CheckSmi(ToRegister(input));