[Support] Fix `-ftime-trace-granularity` option

Summary:
Move `-ftime-trace-granularity` option to frontend options. Without patch
this option is showed up in the help for any tool that links libSupport.

Reviewers: sammccall

Subscribers: hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D65202

llvm-svn: 366911