[llvm] [X86][GlobalISel] Enable G_BRJT (PR #81811)

[Craig Topper via llvm-commits]

topperc wrote:

I have a patch for RISC-V to legalize BR_JT to address calculation and BR_INDIRECT. https://github.com/llvm/llvm-project/pull/73711 some of that could be made generic. I just haven't had time to work on GISel recently.

https://github.com/llvm/llvm-project/pull/81811