[llvm-objcopy] Reorder --dump-section before --remove-section for ELF

Reorder `DumpSection` under `handleArgs` in file `ELFObjcopy.cpp`.
`DumpSection` is placed before `replaceAndRemoveSections` and is
therefore now the first operation under `handleArgs`. Thus, it is now
performed before both `add` and `remove` section operations.

Change for the MachO format at D81123. Together fixes https://bugs.llvm.org/show_bug.cgi?id=44283.

Reviewed By: alexshap, jhenderson, MaskRay

Differential Revision: https://reviews.llvm.org/D81097