Revert "D3D11: Refactor InputLayout cache." Seems to be failing maps_pixel_test on the bots. BUG=angleproject:959 This reverts commit 53fd1552ba7dbf91a726fce139d748860bd8a5f5. Change-Id: I1f2593caca58f701d284993d2ee313846806491b Reviewed-on: https://chromium-review.googlesource.com/283157 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>