Remove another method from FoundationTestCase; use a static import instead.

--
MOS_MIGRATED_REVID=98914983
diff --git a/src/test/java/com/google/devtools/build/lib/testutil/FoundationTestCase.java b/src/test/java/com/google/devtools/build/lib/testutil/FoundationTestCase.java
index e618460..62298ef 100644
--- a/src/test/java/com/google/devtools/build/lib/testutil/FoundationTestCase.java
+++ b/src/test/java/com/google/devtools/build/lib/testutil/FoundationTestCase.java
@@ -136,9 +136,4 @@
   protected void assertContainsEventsInOrder(String... expectedMessages) {
     MoreAsserts.assertContainsEventsInOrder(eventCollector, expectedMessages);
   }
-
-  protected static <T> void assertContainsSubset(Iterable<T> arguments,
-                                                 Iterable<T> expectedSubset) {
-    MoreAsserts.assertContainsSubset(arguments, expectedSubset);
-  }
 }