When detecting the target platform, also check if it has threading and
whether the GIL is enabled or not (using the new attribute
`sys.implementation._thread`). If threading is available, add the thread
tests to the set of tests to run (unless the set of tests is explicitly
given).
With this change, the unix port no longer needs to explicitly run the set
of thread tests, so that line has been removed from the Makefile.
This change will make sure thread tests are run with other testing
combinations. In particular, thread tests are now run:
- on the unix port with the native emitter
- on macOS builds
- on unix qemu, the architectures MIPS, ARM and RISCV-64
Signed-off-by: Damien George <damien@micropython.org>
167c888df9