[llvm] Add a pass to convert jump tables to switches. (PR #77709)

[Alexander Shaposhnikov via llvm-commits]

alexander-shaposhnikov wrote:

Fwiw, I've logged more data (from quite a large build - the optimization kicked in ~10K times), in 80% of the cases the max size of the functions in the jump table is less than 25 instructions, and in 90% - less than 37 instructions.
Added an option to apply this transformation only if all the functions are small (i.e. less than the threshold).

https://github.com/llvm/llvm-project/pull/77709