Spec: skip failing spec in react gradebook

React gradebook is not in production. This spec is failing
legitimately but will not be fixed until react gradebook
is again given dev attention.

Change-Id: I5a1d2c40c18b4c42099a0460bc634998b1c99577
Reviewed-on: https://gerrit.instructure.com/83974
Tested-by: Jenkins
Reviewed-by: Matt Fairbourn <mfairbourn@instructure.com>
Product-Review: Matt Fairbourn <mfairbourn@instructure.com>
QA-Review: Matt Fairbourn <mfairbourn@instructure.com>

Author: beckesea

spec/selenium/gradebook/gradebook_performance/gradebook_performance_spec.rb

@@ -187,6 +187,7 @@ def visible_students
     end
 
     it "does not include non-graded group assignment in group total" do
+      skip('Broken and throwing false positives, fix with react gradebook')
       driver.manage.window.maximize
       gc = group_category
       graded_assignment = @course.assignments.create!({