[llvm] [llvm][llvm-lit] Add option to create unique result file names if results already exist (PR #112729)

[David Spickett via llvm-commits]

DavidSpickett wrote:

A question might be "why can't we just use check-all in CI?". We cannot do that because sometimes in CI we need to disable the tests of a single project, but may continue building that project. Or it may be a dependency of a project we do test, but its tests do not work in CI.

https://github.com/llvm/llvm-project/pull/112729