[llvm] Add regression test for libcxx copy_file infinite loop issue (#169261) (PR #169288)

[Sam James via llvm-commits]

thesamesam wrote:

> The test file is named assert.copy_file.pass.cpp following the naming convention for regression tests

It is not named that.

> The test is located in the appropriate directory structure under libcxx/test/libcxx/

No, it isn't, it's at the top-level of the repository. It also isn't wired up to the testsuite framework or the build system at all.

https://github.com/llvm/llvm-project/pull/169288