Options.td: fold the NoForward flag into DriverOption

They seemed to have the same implications, and this makes for one
less flag to worry about.

Differential Revision: http://llvm-reviews.chandlerc.com/D1219

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@187168 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed