[AArch64] [COFF] Move jump tables back to the readonly section

This essentially reverts f5884d25
(D57277).

That commit was made as a workaround since LLVM back then didn't
support cross-section relative relocations (IMAGE_REL_ARM64_REL32)
in COFF for ARM64. Support for this was implemented later,
in d5c5cf5c (D99572) and
382c505d (D102217).

The commit that moved jump tables to the function section noted
that it woud be ideal to utilize IMAGE_REL_ARM64_REL32.

Differential Revision: https://reviews.llvm.org/D113576