Add offscreen-canvas to the list of wpt directories to skip.

third_party/WebKit/LayoutTests/imported/wpt/offscreen-canvas/fill-and-stroke-styles/2d.fillStyle.parse.invalid.hsl-5.worker.js

-// DO NOT EDIT! This test has been generated by tools/gentest.py.
-// OffscreenCanvas test in a worker:2d.fillStyle.parse.invalid.hsl-5
-// Description:
-// Note:
-
-importScripts("/resources/testharness.js");
-importScripts("/common/canvas-tests.js");
-
-var t = async_test("");
-t.step(function() {
-
-var offscreenCanvas = new OffscreenCanvas(100, 50);
-var ctx = offscreenCanvas.getContext('2d');
-
-
-ctx.fillStyle = '#0f0';
-try { ctx.fillStyle = 'hsl(0, 100.%, 50%)'; } catch (e) { } // this shouldn't throw, but it shouldn't matter here if it does
-ctx.fillRect(0, 0, 100, 50);
-_assertPixel(offscreenCanvas, 50,25, 0,255,0,255, "50,25", "0,255,0,255");
-
-t.done();
-
-});
-done();