j2k: flatten test cases and testData directory structure

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

j2k/testData/fileOrElement/inheritance/classOneExtendsBaseGeneric.java

@@ -0,0 +1,13 @@
+//file
+class Base<T> {
+  Base(T name) { }
+}
+
+class One<T, K> extends Base<T> {
+  private K mySecond;
+
+  One(T name, K second) {
+    super(name)
+    mySecond = second;
+  }
+}