[llvm] [GlobalISel] Optimize ULEB128 usage (PR #90565)

[Pierre van Houtryve via llvm-commits]

Pierre-vh wrote:

@aemerson In one test, I observed a small decrease in MatchTable time with this. From about 7.6% to 6.6% of a build.
If you have some time for it, can you check the compiler time too?

https://github.com/llvm/llvm-project/pull/90565