Fix missing import

Author: labkey-tchad

study/test/src/org/labkey/test/tests/study/AssayTest.java

@@ -54,6 +54,7 @@
 import org.labkey.test.util.data.TestArrayDataUtils;
 import org.labkey.test.util.data.TestDataUtils;
 
+import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;