[BUG]: clang-rocm compilers refer to objdump-llvm that doesn't exist

### Describe the bug

https://github.com/compiler-explorer/compiler-explorer/pull/5569/files#r1351103381

```
Oct/10 00:59 admin-node~ 0.5s $ ls -l /opt/compiler-explorer/ | grep rocm
drwxr-xr-x 8 root root 6144 Sep 21 2022 clang-rocm-4.5.2
drwxr-xr-x 8 root root 6144 Sep 21 2022 clang-rocm-5.0.2
drwxr-xr-x 8 root root 6144 Sep 21 2022 clang-rocm-5.1.3
drwxr-xr-x 8 root root 6144 Sep 21 2022 clang-rocm-5.2.3
drwxr-xr-x 8 root root 6144 Nov 17 2022 clang-rocm-5.3.2
drwxr-xr-x 8 root root 6144 Oct 9 23:50 clang-rocm-5.7.0
lrwxrwxrwx 1 root root 25 Oct 9 07:08 clang-rocm-trunk -> clang-rocm-trunk-20231009
drwxr-xr-x 8 root root 6144 Oct 3 07:07 clang-rocm-trunk-20231003
drwxr-xr-x 8 root root 6144 Oct 4 07:12 clang-rocm-trunk-20231004
drwxr-xr-x 8 root root 6144 Oct 5 07:09 clang-rocm-trunk-20231005
drwxr-xr-x 8 root root 6144 Oct 6 07:10 clang-rocm-trunk-20231006
drwxr-xr-x 8 root root 6144 Oct 7 07:09 clang-rocm-trunk-20231007
drwxr-xr-x 8 root root 6144 Oct 8 07:07 clang-rocm-trunk-20231008
drwxr-xr-x 8 root root 6144 Oct 9 07:08 clang-rocm-trunk-20231009
```
no `clang-rocm-405020` or whatever

### Steps to reproduce

na

### Expected behavior

objdump llvms to either not be specified, or to exist

### Reproduction link

Not applicable

### Screenshots

Not applicable

### Operating System

_No response_

### Browser version

_No response_