[llvm] [PAC][CodeGen][ELF][AArch64] Support signed GOT (PR #96164)

[Fangrui Song via llvm-commits]

================
@@ -0,0 +1,82 @@
+; RUN: llc -mtriple=aarch64-linux-gnu -global-isel=0 -fast-isel=0         -verify-machineinstrs \
----------------
MaskRay wrote:

A filename that starts with `ptrauth-` might be better to group ptrauth tests together.
I am not sure the test should focus specifically on PIC. It's common to test both non-pic and pic in one test.

https://github.com/llvm/llvm-project/pull/96164