H2CacheTest: Suppress unchecked type warning

Change-Id: I1d049cfe2d785303c06f5e628884a0c3f9b843e7
diff --git a/javatests/com/google/gerrit/server/cache/h2/H2CacheTest.java b/javatests/com/google/gerrit/server/cache/h2/H2CacheTest.java
index ddcfe0c..3ade4d0 100644
--- a/javatests/com/google/gerrit/server/cache/h2/H2CacheTest.java
+++ b/javatests/com/google/gerrit/server/cache/h2/H2CacheTest.java
@@ -188,6 +188,7 @@
     assertThat(h2Cache.getIfPresent("foo")).isEqualTo("reload:foo");
   }
 
+  @SuppressWarnings("unchecked")
   private static void resetLoaderAndAnswerLoadAndRefreshCalls(CacheLoader<String, String> loader)
       throws Exception {
     reset(loader);