Fix a corner case that involved calling rethrow_if_nested with a type that had a deleted operator&. Added a test to catch this as well. Thanks to Ville for the heads-up.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@255517 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed