gh-98894: Skip dtrace tests when building without dtrace

[stratakis]

Skip functional test_dtrace cases when CPython was not configured with --with-dtrace.

• Issue: Some DTrace probes are broken in 3.11 #98894

[stratakis]

cc @vstinner

[vstinner]

On a Python built without --with-dtrace, test_dtrace runs exactly one function:

test_filter_probe_rows_ignores_warnings (test.test_dtrace.BPFTraceOutputTests.test_filter_probe_rows_ignores_warnings) ... ok

Hum, I'm not sure that it's worth it to run this single test on a Python built without --with-dtrace.

Instead, I suggest running the check at the module top-level and remove the check from CheckDtraceProbes.setUpClass().

Something like:

if not support.has_subprocess_support:
    raise unittest.SkipTest("test module requires subprocess")
if not sysconfig.get_config_var('WITH_DTRACE'):
    raise unittest.SkipTest(
        "CPython must be configured with the --with-dtrace option."
    )

So the whole test is skipped:

0:00:00 load avg: 0.72 mem: 29.9 MiB [1/1] test_dtrace
test_dtrace skipped -- CPython must be configured with the --with-dtrace option.
0:00:00 load avg: 0.72 mem: 31.0 MiB [1/1] test_dtrace skipped