[llvm] [llvm-objcopy] Always update indirectsymoff in MachO (PR #117726)

[Richard Dzenis via llvm-commits]

RIscRIpt wrote:

> Do you think it would be possible to add a test case where there are indirect symbols (or is there an existing test case for that?)

There are some:

```
❯ cd llvm/test/tools/llvm-objcopy/MachO
❯ rg "indirectsymoff:\\s*[1-9]"
linkedit-order-1.test
254:    indirectsymoff:  49424

Inputs/strip-all-with-codesignature.yaml
194:    indirectsymoff:  8424

linkedit-order-2.test
198:    indirectsymoff:  33000

symtbl-zero-indirectsymoff.test
39:    indirectsymoff:  42

remove-lc-index-update.test
194:    indirectsymoff:  8264

symbol-table.test
329:    indirectsymoff:  8480
```

https://github.com/llvm/llvm-project/pull/117726