[PAC][ELF] Implement signed ctor / dtor calls

[asl]

Downstream commit: access-softek/llvm-project@4fb933c

[llvmbot]

@llvm/issue-subscribers-backend-aarch64

Author: Anton Korobeynikov (asl)

Downstream commit: https://github.com/access-softek/llvm-project/commit/4fb933cc2d3629905a7ddf56ae96276484371a3d

[llvmbot]

@llvm/issue-subscribers-clang-driver

Author: Anton Korobeynikov (asl)

Downstream commit: https://github.com/access-softek/llvm-project/commit/4fb933cc2d3629905a7ddf56ae96276484371a3d