fix pytest test failures

[tybug]

Closes #4432.

The healthcheck traceback adds a new marker line. Here's the diff:

=================================== FAILURES ===================================
_____________________ test_healthcheck_traceback_is_hidden _____________________

    @given(integers().map(lambda x: time.sleep(0.2)))
 >   def test_healthcheck_traceback_is_hidden(x):
+                   ^^^
E   hypothesis.errors.FailedHealthCheck: Data generation is extremely slow: Only produced 5 valid examples in 1.02 seconds (0 invalid ones and 0 exceeded maximum size). Try decreasing size of the data you're generating (with e.g. max_size or max_leaves parameters).
E         count | fraction |    slowest draws (seconds)
E     x |    5  |    100%  |   0.203,  0.203,  0.203,  0.203,  0.205
E   See https://hypothesis.readthedocs.io/en/latest/reference/api.html#hypothesis.HealthCheck for more information about this. If you want to disable just this health check, add HealthCheck.too_slow to the suppress_health_check settings for this test.

test_healthcheck_traceback_is_hidden.py:5: FailedHealthCheck
 ---------------------------------- Hypothesis ----------------------------------
You can add @seed(44133051342172786532243155379846778193) to this test or run pytest with --hypothesis-seed=44133051342172786532243155379846778193 to reproduce this failure.
=========================== short test summary info ============================
FAILED test_healthcheck_traceback_is_hidden.py::test_healthcheck_traceback_is_hidden
============================== 1 failed in 1.34s ===============================

This does not point at the correct location, but this isn't the first time our traceback adjustments have caused problems with these error location markers.