[AArch64] [COFF] Properly produce cross-section relative relocations

This fixes breakage on Windows/ARM64 after D94355.

Modelled after the corresponding code for X86; not entirely familiar
with those aspects of that layer otherwise.

Differential Revision: https://reviews.llvm.org/D99572

GitOrigin-RevId: d5c5cf5ce8d921fc8c5e1b608c298a1ffa688d37
3 files changed