work around trunk temp rt issue,

Assets/GraphicsTests/Editor/TestFramework.cs

 			Assert.IsNotNull(testSetup, "No SetupSceneForRenderPipelineTest in scene " + testInfo.name);
 			Assert.IsNotNull(testSetup.cameraToUse, "No configured camera in <SetupSceneForRenderPipelineTest>");
             
+			var rtDesc = new RenderTextureDescriptor (
+				             testSetup.width, 
+				             testSetup.height, 
+				             testSetup.hdr ? RenderTextureFormat.ARGBHalf : RenderTextureFormat.ARGB32,
+				             24);
+			rtDesc.sRGB = PlayerSettings.colorSpace == ColorSpace.Linear;
+
-			var tempTarget = RenderTexture.GetTemporary (testSetup.width, testSetup.height, 24);
+			var tempTarget = RenderTexture.GetTemporary (rtDesc);
 			var oldTarget = testSetup.cameraToUse.targetTexture;
 			testSetup.cameraToUse.targetTexture = tempTarget;
 			testSetup.cameraToUse.Render ();

Assets/GraphicsTests/SetupSceneForRenderPipelineTest.cs

 		private RenderPipelineAsset m_OriginalAsset;
 		public RenderPipelineAsset renderPipeline;
 		public Camera cameraToUse;
+		public bool hdr = false;
 
 		public int width = 1280;
 		public int height = 720;