[build] Enable v8 backtrace on all standalone bots

infra/mb/mb_config.pyl

 # Copyright 2016 The V8 project authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   # This is a map of buildbot master names -> buildbot builder names ->
   # config names (where each config name is a key in the 'configs' dict,
   # below). MB uses this dict to look up which config to use for a given bot.
   # Bots are ordered by appearance on waterfall.
   'masters': {
@@ skipping 420 matching lines @@
     'crosscompile': {
       'gyp_crosscompile': True,
     },
 
     'dcheck_always_on': {
       'gn_args': 'dcheck_always_on=true',
       'gyp_defines': 'dcheck_always_on=1',
     },
 
     'debug': {
-      'gn_args': 'is_debug=true',
+      'gn_args': 'is_debug=true v8_enable_backtrace=true',
+      'gyp_defines': 'v8_enable_backtrace=1',
     },
 
     'debug_bot': {
       'mixins': [
         'debug', 'static', 'goma', 'v8_enable_slow_dchecks',
         'v8_optimized_debug'],
     },
 
     'debug_trybot': {
       'mixins': ['debug_bot', 'minimal_symbols'],
@@ skipping 208 matching lines @@
       'gn_args': 'target_cpu="x64"',
       'gyp_defines': 'target_arch=x64',
     },
 
     'x86': {
       'gn_args': 'target_cpu="x86"',
       'gyp_defines': 'target_arch=ia32',
     },
   },
 }