Let escape_javascript handle conversion to string

This brings `escape_javascript` in line with the behavior of `json_escape` and
allows other value types to be output without needing explicit casting in the
view template.

Example:

    <%= javascript_tag do %>
      var locale = '<%== j I18n.locale %>'; // locale is a symbol
    <% end %>

actionview/lib/action_view/helpers/javascript_helper.rb

@@ -25,12 +25,13 @@ module JavaScriptHelper
       #
       #   $('some_element').replaceWith('<%= j render 'some/element_template' %>');
       def escape_javascript(javascript)
-        if javascript
-          result = javascript.gsub(/(\\|<\/|\r\n|\342\200\250|\342\200\251|[\n\r"'])/u) { |match| JS_ESCAPE_MAP[match] }
-          javascript.html_safe? ? result.html_safe : result
+        javascript = javascript.to_s
+        if javascript.empty?
+          result = ""
         else
-          ""
+          result = javascript.gsub(/(\\|<\/|\r\n|\342\200\250|\342\200\251|[\n\r"'])/u) { |match| JS_ESCAPE_MAP[match] }
         end
+        javascript.html_safe? ? result.html_safe : result
       end
 
       alias_method :j, :escape_javascript

actionview/test/template/javascript_helper_test.rb

@@ -23,6 +23,10 @@ def teardown
 
   def test_escape_javascript
     assert_equal "", escape_javascript(nil)
+    assert_equal "123", escape_javascript(123)
+    assert_equal "en", escape_javascript(:en)
+    assert_equal "false", escape_javascript(false)
+    assert_equal "true", escape_javascript(true)
     assert_equal %(This \\"thing\\" is really\\n netos\\'), escape_javascript(%(This "thing" is really\n netos'))
     assert_equal %(backslash\\\\test), escape_javascript(%(backslash\\test))
     assert_equal %(dont <\\/close> tags), escape_javascript(%(dont </close> tags))