[llvm-branch-commits] [NFCI][ELF][AArch64] Teach addRelativeReloc to emit R_AARCH64_AUTH_RELATIVE (PR #171180)

[Jessica Clarke via llvm-branch-commits]

https://github.com/jrtc27 created https://github.com/llvm/llvm-project/pull/171180

This allows R_AARCH64_AUTH_ABS64 to follow R_AARCH64_ABS64's flow rather
than being implemented in the side in the place that is normally for
symbolic relocations.

Note that this has one implementation change: the RelExpr passed to
relaDyn is now RE_AARCH64_AUTH rather than R_ABS, but the two are
handled identically by InputSectionbase::getRelocTargetVA, and it was
inconsistent with relrAuthDyn which was passed RE_AARCH64_AUTH.