Those are the changes with the current behavior from the behavior in 3.5 observed at the time of the initial bug report:
  python 3.7:
    return.py    Unchanged.
    exception.py After a jump from the 'exception' event into the previous statement, the ensuing 'step' command triggers a trace 'return' event.
    jump.py      The sequence of trace events is unchanged and Python aborts now at the last 'step' command with:
                   python: Python/ceval.c:1083: _PyEval_EvalFrameDefault: Assertion `STACK_LEVEL() <= co->co_stacksize' failed.
  python 3.8:
    return.py    Unchanged.
    exception.py Unchanged from 3.7.
    jump.py      The sequence of trace events is unchanged and the last 'step' command prints now the cryptic error msg:
                   TypeError: 'NoneType' object is not callable
                   > /path/to/jump.py(2)gen()->0
                   -> for i in range(1):

Applying the last patch fixes both 3.7 and 3.8. I can build a PR from this patch. An explanation should be given for the behavior of 3.7 and 3.8 in the jump.py case.