Relates #3258
After a chat with @aslushnikov we add this in two iterations. The first one (this PR) is about scheduled runs for testing the latest tip-of-tree version of the browsers daily and the next PR is about opening an automated PRs once its passing (not sure if its worth to add for failing too) or sending Telegram/Slack notifications.
Current status is that Firefox (around 2 hours) and WebKit (around 3-4 hours) works.
Known issues which I fix before we merge:
- ~~Changes in `test/base.fixture.ts` will get extracted in #3453~~
Feel free to review, current blockers are before we can merge:
- ~~#3453~~
- potential git clone optimisation by aslushnikov
Currently, it might happen that two different patches clash for the
same build number for the browsers. In this case, authors might
not even know that they need to rebaseline.
This patch starts adding a second line to `BUILD_NUMBER` files - the
signature and date of the `BUILD_NUMBER` change. These are guaranteed
to clash, so it should not be possible to land patches without
re-baselining them.
This changes `export.sh` to export diffs instead of patches.
`export.sh` now does not touch working directory, thus not
triggering clean builds and not intefering with an on-going
build.
