Fix IsDeletable() for HStringAdd, HStringCharCodeAt, HStringCharFromCode.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 707e81842f8364ac000a742f936b2b6b38838762..6210a705df71ebaa6519f2d907e94d4facd8bc72 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -3685,11 +3685,6 @@ Representation HUnaryMathOperation::RepresentationFromInputs() {
 }
 
 
-HType HStringCharFromCode::CalculateInferredType() {
-  return HType::String();
-}
-
-
 void HAllocate::HandleSideEffectDominator(GVNFlag side_effect,
                                           HValue* dominator) {
   ASSERT(side_effect == kChangesNewSpacePromotion);