CDRIVER-4682 Detect non-MongoDB host names before SRV lookup. (#1401)

* print failing URI on test failure

* refactor `_detect_nongenuine_hosts` to use separate helper and accept `mongoc_uri_t`

* move `_detect_nongenuine_hosts` earlier

This is intended to ease testing. Tests using bogus URIs will fail SRV lookup. Checking before SRV lookup allows tests to observe the log.

* check SRV hostname

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Co-authored-by: Jeremy Mikola <jmikola@gmail.com>
Co-authored-by: Ezra Chung <88335979+eramongodb@users.noreply.github.com>