Move FindCodeObject from Heap to Isolate.

src/isolate.cc

Index: src/isolate.cc
diff --git a/src/isolate.cc b/src/isolate.cc
index ece024cdbcf90fa14a91715c2cb86da7dba858e1..4adcd69d3f3c5b3a88ffa97636af6139132bed32 100644
--- a/src/isolate.cc
+++ b/src/isolate.cc
@@ -2510,6 +2510,11 @@ CodeStubInterfaceDescriptor*
 }
 
 
+Object* Isolate::FindCodeObject(Address a) {
+  return inner_pointer_to_code_cache()->GcSafeFindCodeForInnerPointer(a);
+}
+
+
 #ifdef DEBUG
 #define ISOLATE_FIELD_OFFSET(type, name, ignored)                       \
 const intptr_t Isolate::name##_debug_offset_ = OFFSET_OF(Isolate, name##_);