[CI] Setup generate_report to describe ninja failures
This patch makes it so that generate_report will add information about
failed build actions to the summary report. This makes it significantly
easier to find compilation failures, especially given we run ninja with
-k 0.
This patch only does the integration into generate_report (along with
testing). Actual utilization in the script is split into a separate
patch to try and keep things clean.
Reviewers: dschuff, cmtice, DavidSpickett, Keenuts, lnihlen, gburgessiv
Reviewed By: cmtice, DavidSpickett
Pull Request: https://github.com/llvm/llvm-project/pull/152621
