Added a NaN/Inf tracker to the debug modes

Assets/ScriptableRenderPipeline/HDRenderPipeline/Debug/DebugDisplay.cs

         None,
         SSAO,
         SSAOBeforeFiltering,
-        MotionVectors
+        MotionVectors,
+        NanTracker
     }
 
     [Serializable]

Assets/ScriptableRenderPipeline/HDRenderPipeline/Debug/DebugDisplay.cs.hlsl

 #define FULLSCREENDEBUGMODE_SSAO (1)
 #define FULLSCREENDEBUGMODE_SSAOBEFORE_FILTERING (2)
 #define FULLSCREENDEBUGMODE_MOTION_VECTORS (3)
+#define FULLSCREENDEBUGMODE_NAN_TRACKER (4)
 
 
 #endif

Assets/ScriptableRenderPipeline/HDRenderPipeline/Debug/DebugFullScreen.shader

                 {
                     return 1.0f - SAMPLE_TEXTURE2D(_DebugFullScreenTexture, sampler_DebugFullScreenTexture, input.texcoord).xxxx;
                 }
+                if (_FullScreenDebugMode == FULLSCREENDEBUGMODE_NAN_TRACKER)
+                {
+                #if UNITY_UV_STARTS_AT_TOP
+                    input.texcoord.y = 1.0 - input.texcoord.y;
+                #endif
+
+                    float4 color = SAMPLE_TEXTURE2D(_DebugFullScreenTexture, sampler_DebugFullScreenTexture, input.texcoord);
+
+                    if (any(isnan(color)) || any(isinf(color)))
+                    {
+                        color = float4(1.0, 0.0, 1.0, 1.0);
+                    }
+                    else
+                    {
+                        // Dim the color buffer so we can see NaNs & Infs better
+                        color.rgb *= 0.25;
+                    }
+
+                    return color;
+                }
                 if (_FullScreenDebugMode == FULLSCREENDEBUGMODE_MOTION_VECTORS)
                 {
                     float2 mv = SampleMotionVectors(input.texcoord);

Assets/ScriptableRenderPipeline/HDRenderPipeline/HDRenderPipeline.cs

                 // Render all type of transparent forward (unlit, lit, complex (hair...)) to keep the sorting between transparent objects.
                 RenderForward(m_CullResults, camera, renderContext, cmd, false);
 
+                PushFullScreenDebugTexture(cmd, m_CameraColorBuffer, camera, renderContext, FullScreenDebugMode.NanTracker);
+
                 // Planar and real time cubemap doesn't need post process and render in FP16
                 if (camera.cameraType == CameraType.Reflection)
                 {