Use StringBssEntry for testing PC-relative patching.

Prepares for removal of LinkerPatch::Type::kDexCacheArray.

Test: m test-art-host-gtest
Bug: 30627598
Change-Id: I69104892447a3b210228fceacf4bfdfd856d5866
diff --git a/compiler/linker/multi_oat_relative_patcher.h b/compiler/linker/multi_oat_relative_patcher.h
index 247b290..bdc1ee1 100644
--- a/compiler/linker/multi_oat_relative_patcher.h
+++ b/compiler/linker/multi_oat_relative_patcher.h
@@ -102,7 +102,7 @@
     relative_patcher_->PatchCall(code, literal_offset, patch_offset, target_offset);
   }
 
-  // Wrapper around RelativePatcher::PatchDexCacheReference(), doing offset adjustment.
+  // Wrapper around RelativePatcher::PatchPcRelativeReference(), doing offset adjustment.
   void PatchPcRelativeReference(std::vector<uint8_t>* code,
                                 const LinkerPatch& patch,
                                 uint32_t patch_offset,