test(project): close the gaps the merge-wave reviews left in the new guard tests #1902

The cross-reviews of the last merge wave left four test gaps unfixed because none of them blocked a PR. Each new check should fail when shown the case it currently misses.

• test(project): keep the #1851 and #1878 tests green on the KTLO legs (#1898, #1899) #1900: tests/project/test_ast_unparse_is_gated_1899_unit.py accepts four cases it should flag:

  • an ast.unparse in the else: branch of a version gate;
  • a gate written the wrong way round, if sys.version_info < (3, 9):;
  • skipIf(sys.version_info >= (3, 9));
  • getattr(ast, 'unparse').

  Only the true branch of a correctly directed comparison should count as gated.

• docs(const): drop version directives from generated tables (#1884) #1895: the directive regex at tests/project/test_no_version_directives_in_generated_tables_1884_unit.py:42, \.\. version(?:added|changed|removed)::, misses .. versionchanged:: written with two spaces, which is valid reST. Use \.\.\s+.

• ci(conda): move platform pins up and give them a review-by date (#1851) #1885: the workflow-install test in tests/project/test_conda_platform_pin_refresh_1851.py splits the install line with shlex.split without comment handling. It passes if requests appears only after a #, and it rejects requests[socks] and requests>=2.

• test(protocols): the #1889 swallowed-raise test can see the deadline arrive without the swallow #1897: the time_limit(1) tests in tests/test_support_helpers.py are open to the stall race test(protocols): keep the #1889 spin's first raise inside its try (#1897) #1901 fixed. If the runner stalls for a second before the block's try, the raise lands outside it.