Fix MB configurations for Mac and Win GN bots.

The windows bots were incorrectly doing 64-bit builds, and the
debug bots (both mac and win) were incorrectly doing shared builds.

TBR=phajdan.jr@chromium.org
BUG=454413
CQ_EXTRA_TRYBOTS=tryserver.chromium.win:win8_chromium_gn_rel,win8_chromium_gn_dbg;tryserver.chromium.mac:mac_chromium_gn_rel,mac_chromium_gn_dbg

Review URL: https://codereview.chromium.org/1086163002

Cr-Commit-Position: refs/heads/master@{#325297}

tools/mb/mb_config.pyl

@@ -22,8 +22,10 @@
     'gn_release_bot': ['gn', 'release_bot'],
     'gn_release_bot_x86': ['gn', 'release_bot', 'x86'],
     'gn_release_trybot': ['gn', 'release_trybot'],
+    'gn_release_trybot_x86': ['gn', 'release_trybot', 'x86'],
     'gn_debug_bot': ['gn', 'debug_bot'],
-    'gn_debug_bot_win_x86': ['gn', 'debug_static_bot', 'x86'],
+    'gn_debug_static_bot': ['gn', 'debug_static_bot'],
+    'gn_debug_static_bot_x86': ['gn', 'debug_static_bot', 'x86'],
     'gyp_release_bot': ['gyp', 'release_bot'],
   },
   
@@ -145,11 +147,11 @@
     },
     'chromium.mac': {
       'Mac GN': 'gn_release_bot',
-      'Mac GN (dbg)': 'gn_debug_bot',
+      'Mac GN (dbg)': 'gn_debug_static_bot',
     },
     'chromium.win': {
       'Win8 GN': 'gn_release_bot_x86',
-      'Win8 GN (dbg)': 'gn_debug_bot_win_x86',
+      'Win8 GN (dbg)': 'gn_debug_static_bot_x86',
     },
     'chromium.webkit': {
       'Android GN': 'gn_release_bot',
@@ -172,13 +174,13 @@
       'linux_chromium_gn_upload_x86': 'gn_release_bot_x86',
     },
     'tryserver.chromium.mac': {
-      'mac_chromium_gn_dbg': 'gn_debug_bot',
+      'mac_chromium_gn_dbg': 'gn_debug_static_bot',
       'mac_chromium_gn_rel': 'gn_release_trybot',
       'mac_chromium_gn_upload': 'gn_release_bot',
     },
     'tryserver.chromium.win': {
-      'win8_chromium_gn_dbg': 'gn_debug_bot',
-      'win8_chromium_gn_rel': 'gn_release_trybot',
+      'win8_chromium_gn_dbg': 'gn_debug_static_bot_x86',
+      'win8_chromium_gn_rel': 'gn_release_trybot_x86',
       'win8_chromium_gn_upload': 'gn_release_bot',
     },
   },