Add non-blocking precommit clang-tidy analysis

[AaronBallman]

RFC: https://discourse.llvm.org/t/rfc-add-non-blocking-precommit-clang-tidy-analysis/89917

[AaronBallman]

Put onto the May 6 project council agenda for a decision

[AaronBallman]

The project council discussed this at the May 13th meeting, minutes at: https://docs.google.com/document/d/1tb0vAH-ONYtX_DrpC7rr5fFrbqzm6XY3iPCWgDYYQ4U/edit?usp=sharing

The project council felt there was not consensus to move forward with the RFC yet. The community appears to support the general idea of adding additional checks to CI, but the RFC may be too ambitious in its current form. The recommendation is to scale back the RFC, focusing on a small proposal that can be incrementally broadened as the community finds other desirable checks -- perhaps start with trying to enable only a single check. Please pay special attention to the concerns around how false positives are handled and to the ergonomics of the daily workflow for things like reporting issues back from CI, how patch authors should reproduce failures locally, etc.

[AaronBallman]

Aaron posted the project council discussion to the RFC thread: https://discourse.llvm.org/t/rfc-add-non-blocking-precommit-clang-tidy-analysis/89917/30 so the next steps are for the RFC author.

[AaronBallman]

Moved off the clang area team schedule and onto the project council because this is a project-wide RFC rather than a clang-specific one.