j2k: flatten test cases and testData directory structure

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

j2k/testData/fileOrElement/literalExpression/dollarInsideString.kt

@@ -0,0 +1,14 @@
+package demo
+
+class Test {
+    fun test() {
+        var name = "$$$$"
+        name = name.replaceAll("\\$[0-9]+", "\\$")
+
+        val c = '$'
+        System.out.println(c)
+
+        val C = '$'
+        System.out.println(C)
+    }
+}