[llvm] [llvm-readobj, ELF] Support for reading binary has more than PN_XNUM segments (PR #162648)

[via llvm-commits]

aokblast wrote:

> I'd also recommend you have an llvm-readobj PR and an llvm-objcopy PR, since the two are independent (or at least, llvm-readobj shouldn't depend on llvm-objcopy as a minimum).
The test would fail since objcopy test use readobj to parse the result. Does it matter?

https://github.com/llvm/llvm-project/pull/162648