In our python tests the expect_verbose function can check for presence or absence of verbose traces, but it can't specify the level of expected traces.

For example it'd be useful to check if WT_DEBUG_2 traces are printed for a category, and not just WT_DEBUG_1.

This ticket will update expect_verbose to take a new expected_verbosity field. This single level applies to all expected verbose categories. It checks that:

• The expected_verbosity level traces are present for all provided categories
• No traces above the expected_verbosity level are present

At the end of this ticket test_verbose04 is able to check a config string like "verbose=[api:2,version:3]". It is ok if this check is performed across two calls to expect_verbose such as

with self.expect_verbose([cfg], "WT_VERB_API", self.is_json, level=2) as conn:
    # test code

with self.expect_verbose([cfg], "WT_VERB_VERSION", self.is_json, level=3) as conn:
    # the same test code as above