[llvm] [AArch64] Codegen for new SCVTF/UCVTF variants (FEAT_FPRCVT) (PR #123767)

[Jonathan Thackray via llvm-commits]

https://github.com/jthackray approved this pull request.

LGTM, tests added for when +fprcvt is both present and absent.

https://github.com/llvm/llvm-project/pull/123767