[llvm] [RISCV] Assert extensions are sorted at compile time. NFCI (PR #77442)

[Craig Topper via llvm-commits]

topperc wrote:

I kind of think we should move the extension lists to tblgen so no one has to sort this table manually. We can probably optimize the string lengths better that way by storing them in a big array with sizes like we do in the asm matcher mnemonic table.

https://github.com/llvm/llvm-project/pull/77442