Adding smart_ptr benchmark

Initial draft here:
https://reviews.llvm.org/D22470
... though this is Eric Fiselier's rewrite to fit in with Google
Benchmark.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@277373 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed