Add support for -fno-auto-profile and -fno-profile-sample-use

Summary: We need to be able to disable samplepgo for specific files by supporting -fno-auto-profile and -fno-profile-sample-use

Reviewers: davidxl, dnovillo, echristo

Reviewed By: echristo

Subscribers: echristo, cfe-commits

Differential Revision: https://reviews.llvm.org/D31213

llvm-svn: 298446