spec: stabilize speedgrader timing
spec: stabilize speedgrader timing

refs CNVS-25916

speedgrader has variable load times, and in both builds
sometimes fails for the first dom check after load if everything
isn't loaded yet.  Instead of the sleeps that have been put in before
for the ones that fail most frequently, this adds an intelligent timeout
check to every speedgrader direct url load.  Stabilizes the passrate
of this spec for both require-js and webpack builds

TEST PLAN:
 1) speedgrader_spec should pass in webpack build

Change-Id: I8ccf8850f717ca6816e4f6e9fdcbf4a923398fc1
Reviewed-on: https://gerrit.instructure.com/70370
Tested-by: Jenkins
Reviewed-by: Jon Jensen <44f878afe53efc66b76772bd845eb65944ed8232@instructure.com>
Product-Review: Jon Jensen <44f878afe53efc66b76772bd845eb65944ed8232@instructure.com>
QA-Review: Jon Jensen <44f878afe53efc66b76772bd845eb65944ed8232@instructure.com>

HotChalk/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,dgynn/canvas-lms,SwinburneOnline/canvas-lms,dgynn/canvas-lms,redconfetti/canvas-lms,roxolan/canvas-lms,HotChalk/canvas-lms,djbender/canvas-lms,roxolan/canvas-lms,HotChalk/canvas-lms,fronteerio/canvas-lms,sfu/canvas-lms,roxolan/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,roxolan/canvas-lms,instructure/canvas-lms,dgynn/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,grahamb/canvas-lms,venturehive/canvas-lms,fronteerio/canvas-lms,grahamb/canvas-lms,SwinburneOnline/canvas-lms,venturehive/canvas-lms,matematikk-mooc/canvas-lms,grahamb/canvas-lms,SwinburneOnline/canvas-lms,SwinburneOnline/canvas-lms,grahamb/canvas-lms,dgynn/canvas-lms,sfu/canvas-lms,redconfetti/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,redconfetti/canvas-lms,matematikk-mooc/canvas-lms,djbender/canvas-lms,venturehive/canvas-lms,fronteerio/canvas-lms,instructure/canvas-lms,matematikk-mooc/canvas-lms,venturehive/canvas-lms,instructure/canvas-lms,fronteerio/canvas-lms,sfu/canvas-lms,grahamb/canvas-lms,redconfetti/canvas-lms,HotChalk/canvas-lms,matematikk-mooc/canvas-lms