aarch64 Fedora/RHEL & Intel macOS noGIL workers temporarily offline

[encukou]

The following workers are offline & marked unstable due to hardware issues:

@stratakis:

• cstratak-fedora-stable-aarch64
• cstratak-RHEL8-aarch64

@itamaro:

• itamaro-macos-intel-aws

When they come up, we'll need to revert #618

[itamaro]

the macOS intel worker is back online and marked as stable