The test fails on D3D11, which seems to ignore floor() calls if
they're nested in a particular way with magic multipliers inside.

BUG=chromium:838885
TEST=angle_end2end_tests

Change-Id: I2c8749defa923553bfee69149da15f8e4ddf5096
Reviewed-on: https://chromium-review.googlesource.com/1041959Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>