Pull non-default branch commits selectively

[gbanasiak]

After switching nightlies to non-default branch it was observed commit IDs selected through branch@timestamp notation are not constant, and depend on subsequent merges of default branch (main) into non-default branch.

This PR mitigates this problem by filtering commit IDs of default branch from timestamp-based pulls of non-default branches using main..branch notation of git rev-list command.

[favilo]

Thanks for doing this.

[gbanasiak]

For the record, here's the state of remote branch prepared in git_test.py.

[24-10-01 18:13] grzegorz:pytest-18/rally-unit-test-local-dir0% cd ../rally-unit-test-remote-dir0
[24-10-01 18:13] grzegorz:pytest-18/rally-unit-test-remote-dir0% git-graph
* 0d0f0f1 - (Tue Oct 1 16:13:02 2024 | Tue Oct 1 16:13:02 2024) initial commit - Grzegorz Banasiak (rally-unit-test-remote-only-branch, master)
| * fa85118 - (Tue Oct 1 16:13:02 2024 | Tue Oct 1 16:13:02 2024) initial commit - Grzegorz Banasiak (HEAD -> rally-unit-test-remote-only-branch-non-master)
| * 8ae6d7e - (Tue Oct 1 16:13:02 2024 | Fri Jan 1 01:00:00 2016) initial commit - Grzegorz Banasiak
|/
* dbe1153 - (Tue Oct 1 16:13:02 2024 | Fri Jan 1 00:00:00 2016) initial commit - Grzegorz Banasiak

The unit test verifies whether commit in rally-unit-test-remote-only-branch-non-master branch earlier than 2016-01-01T110000Z is 8ae6d7e. This test could be improved further if we emulated master merge into rally-unit-test-remote-only-branch-non-master with old commit ID.