Disable handle zapping on branch 5.6

BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/arm.gni")
 import("//build/config/dcheck_always_on.gni")
 import("//build/config/mips.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 
@@ skipping 23 matching lines @@
   # Embeds the given script into the snapshot.
   v8_embed_script = ""
 
   # Sets -dENABLE_DISASSEMBLER.
   v8_enable_disassembler = ""
 
   # Sets -dENABLE_GDB_JIT_INTERFACE.
   v8_enable_gdbjit = ""
 
   # Sets -dENABLE_HANDLE_ZAPPING.
-  v8_enable_handle_zapping = true
+  v8_enable_handle_zapping = is_debug
 
   # Enable slow dchecks.
   v8_enable_slow_dchecks = false
 
   # Interpreted regexp engine exists as platform-independent alternative
   # based where the regular expression is compiled to a bytecode.
   v8_interpreted_regexp = false
 
   # Sets -dOBJECT_PRINT.
   v8_object_print = ""
@@ skipping 2939 matching lines @@
   ]
 
   configs = [
     ":external_config",
     ":internal_config_base",
   ]
 }
 
 v8_fuzzer("wasm_data_section_fuzzer") {
 }