Seems to fail the Windows 8 bots in FL9_3 for some reason.

https://build.chromium.org/p/chromium.gpu.fyi/builders/Win8%20Release%20%28NVIDIA%29/builds/20703

VertexAttributeTest.ShortNormalized_ES2_D3D11_9_3
VertexAttributeTest.ShortUnnormalized_ES2_D3D11_9_3

BUG=angleproject:1339
This reverts commit fb57c04c.

Change-Id: I4c678ff6b337e9a3e0a1fc809f96f6b89407ea33
Reviewed-on: https://chromium-review.googlesource.com/332442Reviewed-by: Jamie Madill <jmadill@chromium.org>