[tsan] Fix signals and setjmp/longjmp on OS X

1) There's a few wrongly defined things in tsan_interceptors.cc,
2) a typo in tsan_rtl_amd64.S which calls setjmp instead of sigsetjmp in the interceptor, and
3) on OS X, accessing an mprotected page results in a SIGBUS (and not SIGSEGV).

Differential Revision: http://reviews.llvm.org/D15052

llvm-svn: 254299