There were two identical files named 'min_allocator.h'. Move one of them to /support and delete the other. Then adjust all the tests that used them to include the moved one. No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@195785 91177308-0d34-0410-b5e6-96231b3b80d8