Do not forward multi-view fields to backend on detach
Do not forward multi-view fields to backend on detach

The patch fixes an unexposed bug in FramebufferGL which would pass
an incorrect multi-view state to StateManagerGL on texture detachment.
The bug is not exposed because upon a subsequent syncing step the
correct state is queried and restored from the framebuffer state.

BUG=angleproject:2062
TEST=angle_end2end_tests

Change-Id: Ie0e783c53e87497b3673ef87ab9c53c3c04054a7
Reviewed-on: https://chromium-review.googlesource.com/636369
Commit-Queue: Martin Radev <ce534a10aebedcce16bec16367ddebba08bf8cf0@nvidia.com>
Reviewed-by: Olli Etuaho <38ae6c0e2772a20e8e989f80cb8c99d274e44242@nvidia.com>
Reviewed-by: Corentin Wallez <470c533e86f4f848c98c7e11fffc2d043494a401@chromium.org>

MSOpenTech/angle,ppy/angle,ppy/angle,ppy/angle,MSOpenTech/angle,MSOpenTech/angle,ppy/angle,MSOpenTech/angle