Implement EXT_depth_clamp * Added depthClamp to the RasterizerState * Added DepthWriteTest end2end tests covering both clipped and clamped depth writes Capture * Updated serialized rasterizer state * Updated CaptureMidExecutionSetup OpenGL * Requires GL 3.2 or ARB_depth_clamp on desktop contexts * Maps to EXT_depth_clamp on ES D3D11 * Maps to the opposite of D3D11_RASTERIZER_DESC.DepthClipEnable * The new tests uncover several edge cases where a workaround is needed to implement unextended OpenGL semantics on top of D3D Metal * Maps to the setDepthClipMode command Bug: angleproject:8047 Bug: angleproject:8077 Change-Id: I1b3448e5b84443e4be18af9bc22d2f8495ac8267 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4347753 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Alexey Knyazev <lexa.knyazev@gmail.com>