preload graphql schema for selenium

refs DE-184

Change-Id: Ib7e739826c3455dcca08743c3271bae05c419740
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/244610
Reviewed-by: Ryan Norton <rnorton@instructure.com>
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
QA-Review: Aaron Ogata <aogata@instructure.com>
Product-Review: Aaron Ogata <aogata@instructure.com>

spec/selenium/common.rb

@@ -114,6 +114,12 @@ shared_context "in-process server selenium tests" do
   # set up so you can use rails urls helpers in your selenium tests
   include Rails.application.routes.url_helpers
 
+  prepend_before :all do
+    # building the schema is currently very slow.
+    # this ensures the schema is built before specs are run to avoid timeouts
+    CanvasSchema.graphql_definition
+  end
+
   prepend_before :each do
     resize_screen_to_standard
     SeleniumDriverSetup.allow_requests!