Revert 226920 "Roll Clang 188423:191856."

I suspect this caused a 25% sizes regression on Mac: http://build.chromium.org/f/chromium/perf/mac-release/sizes/report.html?history=150&rev=-1&graph=Chromium.app

> Roll Clang 188423:191856.
> 
> Remove libprofile_rt from package.sh, it doesn't exist after LLVM r191835
> 
> BUG=290204,303886
> R=thakis@chromium.org
> TBR=net owner
> NOTRY=true
> 
> Review URL: https://codereview.chromium.org/25875004

TBR=thakis@chromium.org

Review URL: https://codereview.chromium.org/25988002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226978 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226978