Method to run Node test-runner ignoring/rejecting any `test.only`/`test(..., { only: true }, ...` filters

### What is the problem this feature will solve? Since the resolution of #47945, `node --test` will automatically filter tests which are not marked `.only`, if * any test/suite is marked with `only: true` * AND * `--test-only` is passed a command line flag * OR process-isolation is disabled by `--test-isolation=none` In addition, since #51383, _filtered_ tests/suites are not passed to test-reporters at all. When developing locally, this is convenient. However, when running tests in CI, it means _there is no way to detect whether or not test-filtering is occurring_ when `--test-isolation=none`. This means it's possible for someone to accidentally push a`.only` call, which will silently disable the rest of the tests. It _appears_ that this logic is defined here: * 24 (current LTS): https://github.com/nodejs/node/blob/v24.x/lib/internal/test_runner/harness.js#L47 * current `main`: https://github.com/nodejs/node/blame/f9f343fb8dda773b749db4dee00704f8bbe79c19/lib/internal/test_runner/harness.js#L47 which forces `isFilteringByOnly` to be `true` when `globalOptions.isolation === 'process' || process.env.NODE_TEST_CONTEXT` is `false` (note that this presents a partial workaround for Node 24, but not Node 22 which is still supported until April 2027) ### What is the feature you are proposing to solve the problem? A command-line option that allows running tests in a way that detects accidental inclusions of `{ only: true }` / `it.only` / `describe.only` / etc. #### additional `--test-only` flag features I think the simplest & best option would be to introduce 2 new possible values for the `--test-only` flag: * `--test-only` / `--test-only=true`: The current behavior * `--test-only=false`: * Runs all tests; even if some other tests are marked with `{ only: true }`, tests are NOT filtered out for having `{ only: false }`. * Other filtering (from name patterns) still occurs as normal. * `--test-only=error`: * I think there are several reasonable semantics f…