spec: fix new_files specs to run with chrome.

Test Plan:
- Specs should pass
- Code review

Change-Id: I8dad776ff64c81ce2b0a0efa9afa3007bafe0b7c
Reviewed-on: https://gerrit.instructure.com/74437
Tested-by: Jenkins
Reviewed-by: Pedro Fajardo <pfajardo@instructure.com>
Product-Review: Matt Fairbourn <mfairbourn@instructure.com>
QA-Review: Matt Fairbourn <mfairbourn@instructure.com>

spec/selenium/helpers/files_common.rb

@@ -117,6 +117,7 @@ module FilesCommon
       end
     end
     ff('.btn.btn-primary')[1].click
+    wait_for_ajaximations
   end
 
   def should_make_folders_in_the_menu_droppable

spec/selenium/new_files_student_spec.rb

@@ -9,9 +9,11 @@ describe "better_file_browsing" do
     def student_goto_files
       user_session(@student)
       get "/courses/#{@course.id}/files"
+      wait_for_ajaximations
     end
 
     def verify_hidden_item_not_searchable_as_student(search_text)
+      refresh_page
       student_goto_files
       f("input[type='search']").send_keys "#{search_text}"
       driver.action.send_keys(:return).perform