[llvm] [GlobalISel] Skip match table for opcodes with no combines (PR #196017)

[Cullen Rhodes via llvm-commits]

c-rhodes wrote:

after https://github.com/llvm/llvm-project/pull/196506 https://github.com/llvm/llvm-project/pull/196530 geomean of this PR is down from -0.42% to -0.33%

https://github.com/llvm/llvm-project/pull/196017