Summary: Refactor the previous version method of marking each apple-clang version as UNSUPPORTED and just XFAIL'ing the libcpp-no-deduction-guides instead. This brings this test inline with the same style as iter_alloc_deduction.pass.cpp
Reviewers: EricWF, dexonsmith
Reviewed By: EricWF
Subscribers: EricWF, vsapsai, vsk, cfe-commits
Differential Revision: https://reviews.llvm.org/D44103
llvm-svn: 327178