[Valgrind] Remove safe-browsing suppression which no longer fires.

BUG=101470,339214
TBR=groby@chromium.org

Review URL: https://codereview.chromium.org/149503007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250530 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250530