Adjust maxFractionalDiff for canvas color-space-conversion (#4486)

This was failing for rg11b10ufloat which is new. Rather than
increase the tolerance for all formats, set it specifically for
certain formats.

Author: greggman

src/webgpu/web_platform/copyToTexture/canvas.spec.ts

@@ -836,8 +836,15 @@ g.test('color_space_conversion')
       maxDiffULPsForNormFormat: 1,
     };
     if (srcColorSpace !== dstColorSpace) {
-      // Color space conversion seems prone to errors up to about 0.0003 on f32, 0.0007 on f16.
-      texelCompareOptions.maxFractionalDiff = 0.001;
+      if (dstColorFormat.endsWith('32float')) {
+        texelCompareOptions.maxFractionalDiff = 0.0003;
+      } else if (dstColorFormat.endsWith('16float')) {
+        texelCompareOptions.maxFractionalDiff = 0.0007;
+      } else if (dstColorFormat === 'rg11b10ufloat') {
+        texelCompareOptions.maxFractionalDiff = 0.015;
+      } else {
+        texelCompareOptions.maxFractionalDiff = 0.001;
+      }
     } else {
       texelCompareOptions.maxDiffULPsForFloatFormat = 1;
     }