[sanitizers] Log all output to CrashReport on OS X

Log all of sanitizers' output (not just ASan bug reports) to CrashReport,
which simplifies diagnosing failed checks as well as other errors. This
also allows to strip the color sequences early from the printed buffer,
which is more efficient than what we had perviously.

Differential Revision: http://reviews.llvm.org/D15396

llvm-svn: 256988