test_more_hypothesis sometimes provokes a deadline warning from Hypothesis

[exarkun]

Seen sometimes on the "deprecations" builder:

test_more_hypothesis ...                                               [OK]
hypothesis_temporary_module_ca8c04296f296227cee4b5d10f5c7da8403a9baa:244: HypothesisDeprecationWarning: Test took 224.22ms to run. In future the default deadline setting will be 200ms, which will make this an error. You can set deadline to an explicit value of e.g. 300 to turn tests slower than this into an error, or you can set it to None to disable this check entirely.

The test in question suppresses the "too slow" health check, mistakenly, in an attempt to quiet this. We need to change the deadline, not suppress "too_slow".

It's okay to just quiet this warning because CI uses shared hosts and we can't predict what CPU resources will be available during a test run.

We can quiet this warning across the whole code base by mimicking what's done here: ​https://github.com/LeastAuthority/txkube/pull/181

[exarkun]

Fixed by ​https://github.com/tahoe-lafs/tahoe-lafs/pull/486