Do not enable RTTI with -fexceptions, for PS4

NFC for targets other than PS4.

This patch is a change in behavior for PS4, in that PS4 will no longer enable
RTTI when -fexceptions is specified (RTTI and Exceptions are disabled by default
on PS4). RTTI will remain disabled except for types being thrown or caught.
Also, '-fexceptions -fno-rtti' (previously prohibited on PS4) is now accepted,
as it is for other targets.

This patch removes some PS4 specific code, making the code cleaner.

Also, in the test file rtti-options.cpp, PS4 tests where the behavior is the
same as the generic x86_64-linux are removed, making the test cleaner.

Differential Revision: https://reviews.llvm.org/D46982

llvm-svn: 332784