Split time-multiple-fields-stepup-stepdown-from-renderer.html into two.

In this test, MultipleFieldsTemporalInputTypeView::updateView() is called on every
attribute update (1,000+ times), and it's not trivial to optimize updateView().

This CL splits the test into two, and skip unnecessary attribute update.

BUG=24182

Review-Url: https://codereview.chromium.org/2138633003
Cr-Commit-Position: refs/heads/master@{#404764}
5 files changed