test: fix cleanup regression assertions

Author: georgewfraser

src/test/java/org/javacs/CompletionsTest.java

@@ -2,6 +2,8 @@
 
 import static org.hamcrest.Matchers.*;
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
 import java.io.IOException;