LibWeb: Add tests for ellipses with varying angles and directions

Author: https://github.com/Gingeh
Commit: https://github.com/LadybirdBrowser/ladybird/commit/74e12a9c97e
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/1308

Tests/LibWeb/Screenshot/canvas-arcs-and-ellipses.html

@@ -5,7 +5,7 @@
     image-rendering: pixelated;
   }
 </style>
-<canvas id="canvas" width="125" height="125"></canvas>
+<canvas id="canvas" width="550" height="325"></canvas>
 <script>
   const canvas = document.getElementById("canvas")
 
@@ -19,4 +19,19 @@
   context.ellipse(20,20,15,8,1.2273132071162383,4.1926143018618225,2.8853539230051624);
   context.stroke();
   context.fill();
+
+  for (let i = 0; i < 2; i++) {
+    for (let j = -5; j <= 5; j++) {
+      context.beginPath();
+      let x = 25 + (j + 5) * 50;
+      let y = 150 + i * 50;
+      let radius = 20;
+      let startAngle = 0;
+      let endAngle = (Math.PI * j) / 2;
+      let counterclockwise = i == 1;
+
+      context.arc(x, y, radius, startAngle, endAngle, counterclockwise);
+      context.stroke();
+    }
+  }
 </script>