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

This reverts commit 70510733.

The following code is now incorrectly rejected.

```
% cat neon.c
#include <arm_neon.h>
__attribute__((target("arch=armv8-a")))
uint64x2_t foo(uint64x2_t a, uint64x2_t b) {
  return veorq_u64(a, b);
}
% newclang --target=aarch64-linux-gnu -c neon.c
neon.c:5:10: error: always_inline function 'veorq_u64' requires target feature 'outline-atomics', but would be inlined into function 'foo' that is compiled without support for 'outline-atomics'
    5 |   return veorq_u64(a, b);
      |          ^
1 error generated.
```

"+outline-atomics" seems misleading here.