Expose view url to render function in ScriptTemplateView

After this change, with Nashorn it is possible to use either
render(template, model) or render(template, model, url).
With JRuby or Jython, specifying the 3 parameters is mandatory.

Issue: SPR-13453

spring-webmvc/src/test/resources/org/springframework/web/servlet/view/script/jruby/render.rb

@@ -3,8 +3,7 @@ require 'ostruct'
 require 'java'
 
 # Renders an ERB template against a hashmap of variables.
-# template should be a Java InputStream
-def render(template, variables)
+def render(template, variables, url)
   context = OpenStruct.new(variables).instance_eval do
     variables.each do |k, v|
       instance_variable_set(k, v) if k[0] == '@'

spring-webmvc/src/test/resources/org/springframework/web/servlet/view/script/jython/render.py

@@ -1,5 +1,5 @@
 from string import Template
 
-def render(template, model):
+def render(template, model, url):
 	s = Template(template)
 	return s.substitute(model)

spring-webmvc/src/test/resources/org/springframework/web/servlet/view/script/nashorn/render.js

@@ -1,3 +1,7 @@
 function render(template, model) {
     return template.replace("{{title}}", model.title).replace("{{body}}", model.body);
-}
+}
+
+function renderWithUrl(template, model, url) {
+    return template.replace("{{title}}", "Check url parameter").replace("{{body}}", url);
+}