[Win32] Let utils/not aware of abort(), aka llvm_unreachable(), in msvcrt.

It has exit code as 3. abort(), aka unreachable, may be handled as crash.

FIXME: Could we move this into Win32/Program.inc?

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210895 91177308-0d34-0410-b5e6-96231b3b80d8