Android: Changes that improve AArch64 Android cannot be tested on 32-bit ARM Android

Currently we cannot test the runtime behaviour of 32-bit ARM Android, and so when making changes to DR that are known to work on and improve 64-bit AArch64 Android, we do not know if the change would benefit 32-bit Android or not.

To reduce the risk of breaking 32-bit Android, most of these changes will be applicable to 64-bit Android only, even if they might benefit or fix issues on 32-bit Android as well.

If these types of changes are linked with this issue then hopefully the changes can be easily found and tested on 32-bit Android if the hardware/effort becomes available.