j2k: flatten test cases and testData directory structure

Move j2k/test/tests -> j2k/tests, j2k/test/testData -> j2k/testData

j2k/testData/fileOrElement/equals/Equals2.java

@@ -0,0 +1,9 @@
+class C{
+    boolean foo1(String s1, String s2) {
+        return s1.equals(s2)
+    }
+
+    boolean foo2(String s1, String s2) {
+        return !s1.equals(s2)
+    }
+}