[llvm] [X86] matchAddressRecursively - move ZERO_EXTEND patterns into matchIndexRecursively (PR #85081)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon commented:

I'm not sure about this - the point of matchIndexRecursively was that it could improve the indexReg / AM.scale values as it worked up the tree, its not designed to fail in anyway, just stop recursing.

Technically matchIndexRecursively could return void and it updates the AM.IndexReg internally (like it does AM.Scale), I didn't do it that way as I felt the recursion worked better by setting the value on return, but I may have been wrong.

https://github.com/llvm/llvm-project/pull/85081