[clang] [llvm] [AArch64][RISCV] Improve the tests for --print-enabled-extensions and --print-supported-extensions (PR #97829)

[David Spickett via cfe-commits]

DavidSpickett wrote:

Re. the test failure, I've been disabling these and collecting them in https://github.com/llvm/llvm-project/issues/97712. Let me know if you see any others.

https://github.com/llvm/llvm-project/pull/97829