Reland "[AArch64] Decouple feature dependency expansion. (#94279)" (#95231)

My reverted attempt to decouple feature dependency expansion (see
#95056) made it evident that some features are still using the FMV
dependencies in the target attribute.

The original commit broke the llvm test suite. This was addressed here:
https://github.com/llvm/llvm-test-suite/pull/133. I am now relanding it.