Remove option dictionary from beginLayer calls in manual WPT tests

The options dictionary was removed from the layer spec pull request.
https://crrev.com/c/5904350 made all the generated test validating
that feature tentative, but the manual tests were left untouched.
This CL removes the layer parameter from these tests. That parameter
used to be relevant back when unclosed layers could be presented, but
now, layers never gets rendered until they are closed, which makes the
filter parameter in these tests irrelevant.

Bug: 40249439
Change-Id: I70dbc001e596ce70db6b70b059be2829644c0b24
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6069956
Reviewed-by: Yi Xu <[email protected]>
Commit-Queue: Jean-Philippe Gravel <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1393198}

html/canvas/element/manual/layers/unclosed-layers.html

@@ -13,7 +13,7 @@ <h1>unclosed-layers</h1>
   ctx.fillStyle = 'purple';
   ctx.fillRect(60, 60, 75, 50);
 
-  ctx.beginLayer({filter: {name: 'dropShadow', dx: -2, dy: 2}});
+  ctx.beginLayer();
   ctx.fillRect(40, 40, 75, 50);
   ctx.fillStyle = 'grey';
   ctx.fillRect(50, 50, 75, 50);

html/canvas/offscreen/manual/layers/unclosed-layers.html

@@ -16,7 +16,7 @@ <h1>unclosed-layers</h1>
   ctx.fillStyle = 'purple';
   ctx.fillRect(60, 60, 75, 50);
 
-  ctx.beginLayer({filter: {name: 'dropShadow', dx: -2, dy: 2}});
+  ctx.beginLayer();
   ctx.fillRect(40, 40, 75, 50);
   ctx.fillStyle = 'grey';
   ctx.fillRect(50, 50, 75, 50);

html/canvas/offscreen/manual/layers/unclosed-layers.w.html

@@ -16,7 +16,7 @@ <h1>unclosed-layers</h1>
     ctx.fillStyle = 'purple';
     ctx.fillRect(60, 60, 75, 50);
 
-    ctx.beginLayer({filter: {name: 'dropShadow', dx: -2, dy: 2}});
+    ctx.beginLayer();
     ctx.fillRect(40, 40, 75, 50);
     ctx.fillStyle = 'grey';
     ctx.fillRect(50, 50, 75, 50);