Remove suppressions for http://crbug.com/308683, which is fixed.

It proved possible to get line numbers by building with clang on Linux.

BUG=96684,308683
TBR=thestig@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/30533009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230366 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 230366