[llvm] [RISCV] Use policy instead of ForceTailAgnostic for vmsbf/vmsif/vmsof pseudos. (PR #127535)

[Pengcheng Wang via llvm-commits]

https://github.com/wangpc-pp approved this pull request.

LGTM.
(If we remove `ForceTailAgnostic`, there will be a bubble in TSFlags, should we compact it?)

https://github.com/llvm/llvm-project/pull/127535