generalize pass gpu-kernel-outlining for symbol op (#72074)

This PR generalize gpu-out-lining pass to take care of ops
`SymbolOpInterface` instead of just `func::FuncOp`.

Before this change, gpu-out-lining pass will skip `llvm.func`.
```mlir
module {
  llvm.func @main() {
    %c1 = arith.constant 1 : index
    gpu.launch blocks(%arg0, %arg1, %arg2) in (%arg6 = %c1, %arg7 = %c1, %arg8 = %c1) threads(%arg3, %arg4, %arg5) in (%arg9 = %c1, %arg10 = %c1, %arg11 = %c1) {
      gpu.terminator
    }
    llvm.return
  }
}
```

After this change, gpu-out-lining pass can handle llvm.func as well.