Added support for most of <mutex>

[ogiroux]

trafficstars

Has mutex, timed_mutex, once_flag, call_once, unique_lock, scoped_lock, and varied free functions that go with them. Excludes only condition variable support and the recursive versions of mutex.

[wmaxey]

TODO: Test ports and heterogeneous tests.

[jrhemstad]

@wmaxey @ogiroux is this just waiting on porting tests? I'd like to move forward with exploring https://github.com/NVIDIA/cccl/issues/990, but it depends on having a mutex first.

[miscco]

@jrhemstad How important is this and should I try to get this rebased?

[jrhemstad]

@jrhemstad How important is this and should I try to get this rebased?

It's important, but not urgent. No need to try and get it merged before the next release. There is still a sizable amount of work to add tests before it can be merged anyways.

[miscco]

While everything works fine locally, this PR is incredibly flaky in CI.

We need to investigate why that is the case and find a strategy to unflake it

[miscco]

Dropping in favor of https://github.com/NVIDIA/cccl/pull/187