in commit f25faf58a3ed81 the test runner was converted to a new API
which, instead of running single-step concurrently HDL-Simulator instruction 1,
HDL-Simulator instruction 2, .... it is now HDL instruction 1, HDL instruction 2
... followed separately by Simulator instruction 1, Simulator instruction 2 ...
HDL in SVP64 is not correctly detecting a terminating condition, instead
entering a permanent loop. test_runner.py:
terminated = yield self.issuer.dbg.terminated_o
this is never being set (in svp64 mode) and therefore the HDL simulation