[Feature] Show RepeatEachIndex in HTML Reporter and other reporters

[mxschmitt]

Imagine I debug a flaky test, I do then --repeat-each=20. I then see that its failing 2/20 times. I would love to know which test-results directory belongs to this test, but neither list nor html reporter help me with that

Workaround:

test.info().annotations.push({ type: 'repeat-index', description: test.info().repeatEachIndex.toString() });

at the beginning of the test. This gets then surfaced in HTML Reporter and I know which test-results sub-directory to look for.

[dgozman]

I think the workaround is totally fine!