Support in VMRuntime for allocating "unpadded" arrays.

Bug: 13028925.

Change-Id: I0a53645f0468aaf44d38aabe016cb610fcfefaf7
diff --git a/runtime/class_linker-inl.h b/runtime/class_linker-inl.h
index 3da7409..754d1dd 100644
--- a/runtime/class_linker-inl.h
+++ b/runtime/class_linker-inl.h
@@ -46,6 +46,7 @@
       return array_class;
     }
   }
+  DCHECK(!element_class->IsPrimitiveVoid());
   std::string descriptor("[");
   descriptor += ClassHelper(element_class).GetDescriptor();
   SirtRef<mirror::ClassLoader> class_loader(self, element_class->GetClassLoader());