Remove C++11 specific version of SafeSNPrintf()

Remove C++11 specific version of SafeSNPrintf() as we don't really use C++11 yet
and adding code like this adds a maintenance cost. For example, the code in
question does not build with gcc 4.7 despite C++11 support being enabled.

R=Nico
BUG=233330

Review URL: https://codereview.chromium.org/102993006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239227 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239227