[llvm] [BPF] Remove unused weak symbol __bpf_trap (PR #166003)

[via llvm-commits]

yonghong-song wrote:

The BPF_TRAP is created as
```
  Function::Create(FT, GlobalValue::ExternalWeakLinkage, BPF_TRAP, M);
```
So BPF_TRAP will be used as a global in instructions. So the branch
```
  else if (Op.isSymbol()) { ... }
```
should be considered as dead code and can be removed.

WDYT?



https://github.com/llvm/llvm-project/pull/166003