[llvm-readobj] [COFF] Resolve relocations pointing at section symbols for arm64 too

This syncs parts from the x86 implementation to the ARMWinEH
implementation.

Currently, neither of the compilers targeting COFF/arm64 (MSVC, LLVM)
produce such relocations, but LLVM might after a later patch.

Differential Revision: https://reviews.llvm.org/D109650