[llvm] [AArch64] Remove TargetParser CPU/Arch feature tests (PR #104587)

[Tomas Matheson via llvm-commits]

tmatheson-arm wrote:

> This part of the test that checks that `cortex-a520` is `armv9.2-a` isn't covered by the `-print-enabled-extensions` tests:
> 
> ```
> AArch64CPUTestParams("cortex-a520", "armv9.2-a",
> ```

👍  I am not sure how useful the CPU architecture tests are (vs checking which actual features are available) but I have updated the PR to keep them.

Also removed some unused parameters from the `testAArch64Arch` tests.

https://github.com/llvm/llvm-project/pull/104587