Disabling troublesome unit test.

[jeffctown]

• Disabling troublesome unit test.
• Updating Readme with known issue.

Checklist

• I've checked that all new and existing tests pass
• I've updated the documentation if necessary
• I've added an entry in the CHANGELOG to credit myself

Motivation and Context

Updates according to #230 .

[AliSoftware]

Just dequeuing my notifications rn, I see you have decided to not merge this but just FYI if we were to fail to find a solution and decided to indeed disable the test for CI to be more reliable, I'd at least do it the same way I did for timing tests: wrap them in a big #if condition which would default to true, and make it false on CI by injecting the build setting during rake invocation on CI (see DISABLE_TIMING_TESTS or whatever I called that #if)