3314d5ce4c
Windows: Implement condvar, mutex and rwlock using futex Well, the Windows equivalent: [`WaitOnAddress`,](https://learn.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-waitonaddress) [`WakeByAddressSingle`](https://learn.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-wakebyaddresssingle) and [`WakeByAddressAll`](https://learn.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-wakebyaddressall). Note that Windows flavoured futexes can be different sizes (1, 2, 4 or 8 bytes). I took advantage of that in the `Mutex` implementation. I also edited the Mutex implementation a bit more than necessary. I was having trouble keeping in my head what 0, 1 and 2 meant so I replaced them with consts. I *think* we're maybe spinning a bit much. `WaitOnAddress` seems to be looping quite a bit too. But for now I've keep the implementations the same. I do wonder if it'd be worth reducing or removing our spinning on Windows. This also adds a new shim to miri, because of course it does. Fixes #121949