D3D11: Set SV_Position interpolation for conservative depth HLSL requires centroid interpolation for PS input position if conservative depth output is used and the shader is executing at pixel-frequency. Bug: angleproject:397720825 Change-Id: I2b314e39e40a63cb58e2bdef99ffa842ddaaff0d Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6336827 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Alexey Knyazev <lexa.knyazev@gmail.com>