Add testing infrastructure to check if gdb is available for testing.

Reviewers: echristo, EricWF

Subscribers: mgorny, christof, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67194

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@371120 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed