Fix off by 4 error handling eh_frame hdr.

- Add a new tool that can dump the register information given a pc.
- Add a new offline unwinder test that fails without this change.
- Update unit tests.
- Refactor offline unwind tests to make it easier to add tests.

Bug: 73048324

Test: Passes new unit tests.
Test: Passes libbacktrace unit tests.
Test: Ran debuggerd -b on random processes.
Change-Id: If6c70a044299505c2274ae6888b35bf9ac34b74b
diff --git a/libunwindstack/DwarfEhFrameWithHdr.cpp b/libunwindstack/DwarfEhFrameWithHdr.cpp
index a131abe..9a49013 100644
--- a/libunwindstack/DwarfEhFrameWithHdr.cpp
+++ b/libunwindstack/DwarfEhFrameWithHdr.cpp
@@ -109,7 +109,7 @@
     fde_info_.erase(index);
     return nullptr;
   }
-  info->pc = value + 4;
+  info->pc = value;
   return info;
 }