[llvm] Add more generic `half`/`bfloat` tests (NFC) (PR #157211)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

If you drop the FMA tests, can you directly add coverage for abs/fneg/copysign to the existing half.ll as part of https://github.com/llvm/llvm-project/pull/156343? I don't want to unnecessary split these "list all target" tests, and as far as I can tell the problem for BPF is any test that emits libcalls, which should no longer be the case after that change.

https://github.com/llvm/llvm-project/pull/157211