Fix early return in QCoro::waitFor

[rgriebl]

Calling exit() on a QEventLoop that hasn't even started does nothing:
it will also not prevent it from being started on exec().

[github-actions]

Unit Test Results

  6 files   -   1    6 suites   - 1   2m 42s ⏱️ - 50m 19s
13 tests ±  0  13 ✔️ +1  0 💤 ±0  0 ❌  - 1 
74 runs   - 11  74 ✔️  - 9  0 💤 ±0  0 ❌  - 2 

Results for commit 472d482. ± Comparison against base commit 8d61ace.

♻️ This comment has been updated with latest results.

[danvratil]

Good catch, thank you!

Would you mind adding a testcase for QCoro::waitFor() with an early-return coroutine to tests/task.cpp? There are already some testWaitFor* functions, so just add a variation with an already-finished coroutine, please.

[danvratil]

Awesome, thank you!