- Added an internal constructor that enables the lock to use non-alertable waits
- Non-alertable waits are not forwarded to `SynchronizationContext` wait overrides, are non-message-pumping waits, and are not interruptible
- Updated most of the uses of `Lock` in NativeAOT to use non-alertable waits
- Also simplified the fix in dotnet#94873 to avoid having to do the relevant null checks in various places along the wait path, by limiting the scope of the null checks to the initialization phase

Fixes dotnet#97105