test_runner: only not working properly in subtests

[mcollina]

It seems there is some odd behavior with only and subtests, because I expected the following to pass:

const test = require('node:test')

test('this should be run', { only: true }, (t) => {
  t.test('this should be run', { only: true }, (t) => {
  })

  t.test('this should not be run', (t) => {
  })
})

But it's failing with an odd error

▶ this should be run
  ✔ this should be run (0.320833ms)
  ✖ this should not be run (0.216167ms)
    'test did not finish before its parent and was cancelled'

▶ this should be run (1.850417ms)

ℹ tests 3
ℹ suites 0
ℹ pass 1
ℹ fail 1
ℹ cancelled 1
ℹ skipped 0
ℹ todo 0
ℹ duration_ms 0.11275

✖ failing tests:

✖ this should not be run (0.216167ms)
  'test did not finish before its parent and was cancelled'

[cjihrig]

This is working as documented:

When a test with the only option set is run, all subtests are also run. The test context's runOnly() method can be used to implement the same behavior at the subtest level.

@MoLow is already looking at improving this experience in #48932, so I'll close this issue.