Revert of [crankshaft] Protect against deopt loops from string length overflows.

src/crankshaft/hydrogen.cc

Index: src/crankshaft/hydrogen.cc
diff --git a/src/crankshaft/hydrogen.cc b/src/crankshaft/hydrogen.cc
index a927954be383702be78850549568c899483658fd..e5332a2f5d1a961c6a9eb69da3b29d6390bd22d0 100644
--- a/src/crankshaft/hydrogen.cc
+++ b/src/crankshaft/hydrogen.cc
@@ -2368,7 +2368,7 @@
   HValue* length = AddUncasted<HAdd>(left_length, right_length);
   // Check that length <= kMaxLength <=> length < MaxLength + 1.
   HValue* max_length = Add<HConstant>(String::kMaxLength + 1);
-  if (top_info()->IsStub() || !isolate()->IsStringLengthOverflowIntact()) {
+  if (top_info()->IsStub()) {
     // This is a mitigation for crbug.com/627934; the real fix
     // will be to migrate the StringAddStub to TurboFan one day.
     IfBuilder if_invalid(this);
@@ -2380,7 +2380,6 @@
     }
     if_invalid.End();
   } else {
-    graph()->MarkDependsOnStringLengthOverflow();
     Add<HBoundsCheck>(length, max_length);
   }
   return length;