[Support] Add a test for recursive response file expansion

[Support] Add a test for recursive response file expansion

I'm going to be modifying the logic to avoid infinitely recursing on
self-referential response files, so add a unit test to verify the
expected behavior.

Differential Revision: https://reviews.llvm.org/D60630

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358451 91177308-0d34-0410-b5e6-96231b3b80d8