Add some more PS4 driver settings related to rtti and exceptions.

Summary:
The PS4 defaults to -fno-rtti, and has to have rtti enabled when enabling
exceptions.

This commit makes clang add the -fno-rtti by default on the PS4, unless
-frtti was passed in.

It also diagnoses misuses for the PS4:
- Exceptions need rtti. Warn and enable rtti if no rtti flag was passed,
  error if -fno-rtti was passed.

I also added a more general warning for when -fno-rtti is the default
(currently it's only on the PS4) and the vptr sanitizer is on.

Fixed a few tests, due to different flag order when passing cc1 arguments.

Reviewers: chandlerc

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D7250

llvm-svn: 227518