[llvm] [compiler-rt] [ci] Set timeout for individual tests and report slowest tests (PR #76300)

[Louis Dionne via llvm-commits]

https://github.com/ldionne approved this pull request.

I was OOO until Jan 8th, sorry for the delay. This LGTM, we actually do the same thing for libc++ tests.

https://github.com/llvm/llvm-project/pull/76300