Revert "Enable libstdc++ debug mode in debug builds.".

This reverts commit r24676 to see if it was the cause for the mysterious
crashes on some bots. If not, we'll reland it.

TBR=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/663013002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24715 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

build/standalone.gypi

@@ -136,14 +136,6 @@
     'configurations': {
       'DebugBaseCommon': {
         'cflags': [ '-g', '-O0' ],
-        'conditions': [
-          ['OS=="linux" or OS=="freebsd" or OS=="openbsd" or OS=="netbsd" or \
-            OS=="qnx"', {
-            'defines': [
-              '_GLIBCXX_DEBUG'
-            ],
-          }],
-        ],
       },
       'Optdebug': {
         'inherit_from': [ 'DebugBaseCommon', 'DebugBase2' ],