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

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index f5e043c93c71e2182d8c6ba881fb9332e26ce8a0..e2b82df047161b3feb6c86123692f3024fad279b 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -2911,6 +2911,10 @@ void Heap::CreateInitialObjects() {
       handle(Smi::FromInt(Isolate::kArrayProtectorValid), isolate()));
   set_species_protector(*species_cell);
 
+  cell = factory->NewPropertyCell();
+  cell->set_value(Smi::FromInt(Isolate::kArrayProtectorValid));
+  set_string_length_protector(*cell);
+
   set_serialized_templates(empty_fixed_array());
 
   set_weak_stack_trace_list(Smi::FromInt(0));