Summary:
Benchmarks for construct, find, insert and iterate, with sequential
and random ordered inputs.
It also improves the cartesian product benchmark header to allow for
runtime values to be specified in the product.
Reviewers: EricWF
Subscribers: christof, ldionne, libcxx-commits
Differential Revision: https://reviews.llvm.org/D53523
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@345035 91177308-0d34-0410-b5e6-96231b3b80d8