Move a test to the new tests directory.

I had written the patch that added this test before the tests were
moved into tests/std, so the test ended up in the wrong directory.

llvm-svn: 225300

diff --git a/libcxx/test/atomics/atomics.general/replace_failure_order.pass.cpp b/libcxx/test/std/atomics/atomics.general/replace_failure_order.pass.cpp
similarity index 100%
rename from libcxx/test/atomics/atomics.general/replace_failure_order.pass.cpp
rename to libcxx/test/std/atomics/atomics.general/replace_failure_order.pass.cpp