Remove unused import

Author: dr-jts

modules/core/src/test/java/org/locationtech/jts/geom/TriangleTest.java

@@ -14,7 +14,6 @@
 import org.locationtech.jts.algorithm.Distance;
 import org.locationtech.jts.io.WKTReader;
 
-import junit.framework.TestCase;
 import junit.textui.TestRunner;
 import test.jts.GeometryTestCase;