Replaces tilewms.tests.js with new tests

Transforms the old rendering tests for the TileWMSSource
to the new rendering test approach.

rendering/cases/source-tilewms-gutter0/main.js

@@ -0,0 +1,26 @@
+import Map from '../../../src/ol/Map.js';
+import View from '../../../src/ol/View.js';
+import TileLayer from '../../../src/ol/layer/Tile.js';
+import TileWMS from '../../../src/ol/source/TileWMS.js';
+
+const tileWms = new TileWMS({
+  params: {
+    'LAYERS': 'layer'
+  },
+  gutter: 0,
+  url: '/data/tiles/wms/wms0.png',
+  transition: 0
+});
+
+new Map({
+  pixelRatio: 1,
+  layers: [new TileLayer({source: tileWms})],
+  target: 'map',
+  view: new View({
+    center: [0, 0],
+    zoom: 5
+  })
+});
+
+render();
+