[clang] [llvm] [RISCV] Gate unratified profiles behind -menable-experimental-extensions (PR #92167)

[Alex Bradbury via llvm-commits]

asb wrote:

Thank you for the reviews - I've gone ahead and merged. One thing from the added tests that's worth highlighting perhaps is `RejectsProfilesWithAdditionalExtensionsGivenAlreadyInProfile` which documents that currently if you specify an extension that's already part of the profile then it's rejected. e.g. rva23u64_zfa. Perhaps this is overly restrictive in practice? I've made a note to raise it at the next sync-up call.

https://github.com/llvm/llvm-project/pull/92167