Fix builds under other configurations

Change-Id: Ice6008b644b8a9d4879c007b760ba90b031ec511
diff --git a/third_party/gperftools/BUILD b/third_party/gperftools/BUILD
index 51953b4..65d9b1b 100644
--- a/third_party/gperftools/BUILD
+++ b/third_party/gperftools/BUILD
@@ -231,7 +231,7 @@
     ':tcmalloc',
   ],
   copts = common_copts,
-  size = 'small',
+  size = 'medium',
 )
 
 cc_test(