Removing the HasBuiltinSetjmp flag and associated bits. Flagging the presence

Removing the HasBuiltinSetjmp flag and associated bits. Flagging the presence
of exception handling builtin sjlj targets in functions turns out not to
be necessary. Marking the intrinsic implementation in the .td file as
defining all registers is sufficient to get the context saved properly by
the containing function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71743 91177308-0d34-0410-b5e6-96231b3b80d8