enable "-rtos hwthread"-capable platforms in OpenOCD CI testing.

[aap-sc]

RISC-V tests repository has several platforms, however only spike32.py and spike64-2.py are tested. On the other side there are paltfroms like spike64-2-hwthread.py and spike32-2-hwthread.py that cover some additional functionality. However, currently testing on these platforms fail due to recently-committed regression 7f2d3e2 . See here for details: https://review.openocd.org/c/openocd/+/8471

I think we need to enable tests on these platforms.

@TommyMurphyTM1234 , @JanMatCodasip , @MarekVCodasip , @en-sc - FYI