[Modules] Convert module specific -fno-modules-autolink into -fno-autolink.

 - There is no reason to have a modules specific flag for disabling
   autolinking. Instead, convert the existing flag into -fno-autolink (which
   should cover other autolinking code generation paths like #pragmas if and
   when we support them).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179612 91177308-0d34-0410-b5e6-96231b3b80d8