Metal Bugs specific to the macOS ARM port

[Philip Race]

We have our first couple of bugs that are specific to Apple Silicon 
which were found
when running a native ARM build using Metal on Apple Silicon.

These bugs can be found and distinguished by these fields+values
CPU:aarch64
OS: os_x

Please set these on all such bugs - be sure to use "aarch64" and NOT "arm".

We should also continue to add the "lanai" label

-phil.