[llvm] [GlobalIsel] Combine G_EXTRACT_VECTOR_ELT (PR #85321)

[Thorsten Schütt via llvm-commits]

tschuett wrote:

As I already said: extractVectorElement(fcmp, index) will have a low hitrate and can/will be a unique pattern. extractVectorElement(freeze, index) might be a border line case. I don't want to have two patterns for extractVectorElement(insertVectorElement, index).

https://github.com/llvm/llvm-project/pull/85321