[build] Use shared libraries by default for debug builds

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 241 matching lines @@
       'swarming'],
     'gn_release_simulate_arm64_trybot': [
       'gn', 'release_trybot', 'simulate_arm64', 'swarming'],
     'gn_release_simulate_mipsel': [
       'gn', 'release_bot', 'simulate_mipsel', 'swarming'],
     'gn_release_simulate_mips64el': [
       'gn', 'release_bot', 'simulate_mips64el', 'swarming'],
 
     # GN debug configs for arm.
     'gn_debug_arm': [
-      'gn', 'debug', 'arm',
-      'shared', 'goma', 'v8_enable_slow_dchecks', 'v8_optimized_debug',
-      'crosscompile', 'hard_float', 'swarming'],
+      'gn', 'debug_bot', 'arm', 'crosscompile', 'hard_float', 'swarming'],
 
     # GN release configs for arm.
     'gn_release_arm': [
       'gn', 'release_bot', 'arm', 'crosscompile', 'hard_float', 'swarming'],
     'gn_release_android_arm': [
       'gn', 'release_bot', 'arm', 'android', 'crosscompile', 'swarming'],
     'gn_release_android_arm64': [
       'gn', 'release_bot', 'arm64', 'android', 'crosscompile', 'swarming'],
 
     # GN release configs for x64.
@@ skipping 175 matching lines @@
       'gyp_defines': 'dcheck_always_on=1',
     },
 
     'debug': {
       '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',
+        'debug', 'shared', 'goma', 'v8_enable_slow_dchecks',
         'v8_optimized_debug'],
     },
 
     'debug_trybot': {
       'mixins': ['debug_bot', 'minimal_symbols'],
     },
 
     'edge': {
       'gn_args': 'sanitizer_coverage_flags="edge"',
       'gyp_defines': 'sanitizer_coverage=edge',
@@ skipping 204 matching lines @@
       'gn_args': 'target_cpu="x64"',
       'gyp_defines': 'target_arch=x64',
     },
 
     'x86': {
       'gn_args': 'target_cpu="x86"',
       'gyp_defines': 'target_arch=ia32',
     },
   },
 }