j2k: flatten test cases and testData directory structure

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

j2k/testData/fileOrElement/literalExpression/char.java

@@ -0,0 +1,7 @@
+//file
+class Test {
+  void test() {
+    char c1 = 'c';
+    Character c2 = 'C';
+  }
+}