[llvm] [X86] Remove LowerFCanonicalize and use generic expansion (PR #147730)

[via llvm-commits]

woruyu wrote:

In this patch, vector ISD::FCANONICALIZE is not expanded in VectorLegalizer::Expand — instead, it returns early and defers to DAG legalization, where the generic expansion using STRICT_FMUL is applied.

Is this the right place to handle it, or would it be better to expand vector FCANONICALIZE earlier during vector legalization?

https://github.com/llvm/llvm-project/pull/147730