[X86] Attempt to combine binary shuffles where both operands come from the same larger vector

Allows us to use combineX86ShuffleChainWithExtract to combine targetshuffle(low_subvector(x),high_subvector(x)) -> low_subvector(targetshuffle(x)) style patterns

This is currently very limited (it must have a v2i64/v2f64 result), but while triaging I noticed we might be able to extend this to allow more types for targets with suitable variable cross lane shuffle support.

Fixes #58339