Review commit: https://reviewboard.mozilla.org/r/208246/diff/#index_header See other reviews: https://reviewboard.mozilla.org/r/208246/

`taskgraph.create` can add an additional dependency to tasks prior to task submission. The queue will error out if we submit a task with over 100 dependencies, so we should limit ourselves to 99 dependencies here. Review commit: https://reviewboard.mozilla.org/r/208248/diff/#index_header See other reviews: https://reviewboard.mozilla.org/r/208248/

Review commit: https://reviewboard.mozilla.org/r/208250/diff/#index_header See other reviews: https://reviewboard.mozilla.org/r/208250/

Adjust post-beetmover-dummy's tasks and deps. - Fennec doesn't have beetmover-repackage or beetmover-checksums, so add `beetmover` to the post-beetmover-dummy kind-dependencies. - Add a fennec-promote post-beetmover-dummy job. - Remove the extraneous -ship post-beetmover-dummy jobs. Once we removed the assumption that dummy jobs had to be in the same phase, these became redundant. In testing, this looks good. For the next step, we may want to split these dummy tasks up by `build_platform`. Then downstream tasks could then optionally filter their dummy deps by `build_platform`; this would allow for certain platforms to proceed on to the next steps sooner, rather than wait for the slowest platform to finish. I also suspect we don't need post-beetmover-checksums-dummy at all; it's redundant. Review commit: https://reviewboard.mozilla.org/r/208300/diff/#index_header See other reviews: https://reviewboard.mozilla.org/r/208300/