Fix Path unittests on Windows after raw_fd_ostream changes

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216422 91177308-0d34-0410-b5e6-96231b3b80d8
Declare that musttail calls in variadic functions forward the ellipsis

Summary:
There is no functionality change here except in the way we assemble and
dump musttail calls in variadic functions. There's really no need to
separate out the bits for musttail and "is forwarding varargs" on call
instructions. A musttail call by definition has to forward the ellipsis
or it would fail verification.

Reviewers: chandlerc, nlewycky

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D4892

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216423 91177308-0d34-0410-b5e6-96231b3b80d8
fix typos in comments


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216424 91177308-0d34-0410-b5e6-96231b3b80d8
musttail: Don't eliminate varargs packs if there is a forwarding call

Also clean up and beef up this grep test for the feature.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216425 91177308-0d34-0410-b5e6-96231b3b80d8