Fix --last-failed reported items in terminal

[nicoddemus]

Using the new pytest_report_collectionfinish hook it is now possible to accurately report the items which will be rerun.

Should be reviewed only after #2621 is merged.

[coveralls]

Coverage increased (+0.0009%) to 91.887% when pulling a79d103 on nicoddemus:lf-report-after-collection into e97fd5e on pytest-dev:features.

[coveralls]

Coverage increased (+0.0009%) to 91.887% when pulling 8d83b48 on nicoddemus:lf-report-after-collection into e97fd5e on pytest-dev:features.

[nicoddemus]

Now that #2621 has been merged this is ready for review.

[nicoddemus]

Rebased

[coveralls]

Coverage increased (+0.003%) to 91.887% when pulling 7a12acb on nicoddemus:lf-report-after-collection into 1712196 on pytest-dev:features.