ART: Added DCHECKS to find alignment breakage.

Change-Id: I47aed866ec3c3858dc3ee27cb84cfaddf44009d1
diff --git a/runtime/utils/dex_cache_arrays_layout-inl.h b/runtime/utils/dex_cache_arrays_layout-inl.h
index c2b2f65..4c63156 100644
--- a/runtime/utils/dex_cache_arrays_layout-inl.h
+++ b/runtime/utils/dex_cache_arrays_layout-inl.h
@@ -100,6 +100,8 @@
 }
 
 inline size_t DexCacheArraysLayout::StringsAlignment() const {
+  static_assert(alignof(mirror::StringDexCacheType) == 8,
+                "Expecting alignof(StringDexCacheType) == 8");
   return alignof(mirror::StringDexCacheType);
 }