Clear dex pc to avoid duplicate frames.

Bug: 73228466

Test: Passes new unit tests, fails without change.
Change-Id: I3660bfd16cbf2d5cf96490ca7714bc5f97914884
diff --git a/libunwindstack/Unwinder.cpp b/libunwindstack/Unwinder.cpp
index 644bfa8..dfd7b18 100644
--- a/libunwindstack/Unwinder.cpp
+++ b/libunwindstack/Unwinder.cpp
@@ -175,6 +175,8 @@
       if (regs_->dex_pc() != 0) {
         // Add a frame to represent the dex file.
         FillInDexFrame();
+        // Clear the dex pc so that we don't repeat this frame later.
+        regs_->set_dex_pc(0);
       }
 
       FillInFrame(map_info, elf, adjusted_rel_pc, adjusted_pc);