Fix __is_referenceable to work with vector types. Fixes PR#26654 and 26656. Thanks to Evgeniy for the reports, and to Eric for the suggestion on how to fix it.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@261581 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed