Revert of [build] Switch off warning on gcc bots.

gypfiles/standalone.gypi

 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 485 matching lines @@
             'inherit_from': ['Debug'],
           },
           'Release_x64': {
             'inherit_from': ['Release'],
           },
         }],
       ],
     },
     'conditions':[
       ['clang==0', {
-        'cflags+': [
-          '-Wno-sign-compare',
-          '-Wno-maybe-uninitialized',
-        ],
+        'cflags+': ['-Wno-sign-compare',],
       }],
       ['clang==1 or host_clang==1', {
         # This is here so that all files get recompiled after a clang roll and
         # when turning clang on or off.
         # (defines are passed via the command line, and build systems rebuild
         # things when their commandline changes). Nothing should ever read this
         # define.
         'defines': ['CR_CLANG_REVISION=<!(python <(DEPTH)/tools/clang/scripts/update.py --print-revision)'],
       }],
       ['clang==1 and target_arch=="ia32"', {
@@ skipping 993 matching lines @@
               '-fsanitize=cfi-vcall',
               '-fsanitize=cfi-derived-cast',
               '-fsanitize=cfi-unrelated-cast',
             ],
           }],
         ],
       },
     }],
   ],
 }