j2k: flatten test cases and testData directory structure

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

j2k/testData/fileOrElement/blocks/Blocks.java

@@ -0,0 +1,16 @@
+//method
+void foo() {
+    {
+        int a = 1;
+        bar(a);
+    }
+
+    {
+        int a = 2;
+        bar(a);
+    }
+
+    {
+        bar(3);
+    }
+}