Use HBoundsCheck to check string length.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index f6e22d873f2e894593a0fbf25d7ed9fbb7176469..282fae7800bab93132c198f0c338762c2cce7b74 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -1793,11 +1793,8 @@ HValue* HGraphBuilder::BuildAddStringLengths(HValue* left_length,
                                              HValue* right_length) {
   // Compute the combined string length and check against max string length.
   HValue* length = AddUncasted<HAdd>(left_length, right_length);
-  IfBuilder if_nooverflow(this);
-  if_nooverflow.If<HCompareNumericAndBranch>(
-      length, Add<HConstant>(String::kMaxLength), Token::LTE);
-  if_nooverflow.Then();
-  if_nooverflow.ElseDeopt("String length exceeds limit");
+  HValue* max_length = Add<HConstant>(String::kMaxLength);
+  Add<HBoundsCheck>(length, max_length);
   return length;
 }