Move Semaphores to the new `ZephyrObject` system, allowing the
constructor to be const.  Unfortunately, `Result` isn't generally useful
with const, and as such, this changes the API for `Semaphore::new()` to
just return the semaphore instead of a Result.  Instead, if a semaphore
constructor has inconsitent arguments, it will panic.  Given that
semaphore constructors are generally quite simple, this is a minor
issue.

However, it will involve removing a lot of `.unwrap()` or `.expect(...)`
calls on semaphores.

The samples have been changed for the API change, but mostly not changed
to take advantage of the easier ways to use them.  It is generally no
longer necessary to put semaphores in an Arc or Rc, but just to allocate
them in something like a StaticCell, and then pass them around by
reference.

Signed-off-by: David Brown <[email protected]>

Convert to the new atomic initializer format. This makes the `new()`
constructor `const` allowing queues to be used as statics.

Similar to the API change to Semaphore, the constructor no longer
returns a Result, just the Queue directly.

Signed-off-by: David Brown <[email protected]>

Adapt to the API change in both Semaphore and Queue. This still
allocates using Arc, though.

Signed-off-by: David Brown <[email protected]>

Update the sys Mutex/Condvar to use the new object initialization, and
update the uses.  This requires a few fixes:

- The SimpleTls no longer needs the StaticTls helper, and we can just
  use a plain global static Mutex.
- Bounded channels add items to a free queue during init.  To avoid
  moving this queue after items have been inserted, we place it in a
  box.  Given that the data of bounded queues is also boxed, this isn't
  really a concern.

Signed-off-by: David Brown <[email protected]>

This was an experiment to see if using an atomic to manage semaphore
initialization was workable.  Now that the main Semaphore implementation
works this way, this can just be removed.

Signed-off-by: David Brown <[email protected]>

Drop the iterations so not as much time is spent in CI.  This still
gives meaning functional results for CI, and the increased value can be
used for actual benchmarking.

Signed-off-by: David Brown <[email protected]>

Although there is still a lot of allocation left (the crossbeam API for
channels is kind of built around it), convert the Semaphores in the
benchmark to be static.  This reduces overhead a little bit, because the
reference counts of Arc don't need to be maintained, and also
demonstrates how StaticCell can be used to allocate things like arrays
of objects statically.

Signed-off-by: David Brown <[email protected]>

Clean up formatting

Signed-off-by: David Brown <[email protected]>

Run rustfmt to clean up formatting of the code.

Signed-off-by: David Brown <[email protected]>