Add flags to disable profile generation.

This patch adds flags -fno-profile-instr-generate and
-fno-profile-instr-use, and the GCC aliases -fno-profile-generate and
-fno-profile-use.

These flags are used in situations where users need to disable profile
generation or use for specific files in a build, without affecting other
files.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@244153 91177308-0d34-0410-b5e6-96231b3b80d8