[MS ABI] Update EH emission for MSVC 2015 compatibility

MSVC 2015 renamed the symbol found by name lookup for 'std::terminate'
so we cannot rely on using '?terminate@@YAXXZ'.  Furthermore, it seems
that 2015 will be the first release of MSVC which permits inlining a
function which is noexcept into a function which isn't.  This is
implemented by creating a cleanup for the invoker which jumps to
__std_terminate.  Clang's implementation of this aspect of the MSVC
scheme is slightly less efficient in this respect because we use a
catch handler configured as a catch-all handler instead.

llvm-svn: 236961