message: Fix CI for FeatureOverrides.test.ts (continued).
diff: @@ -9,6 +9,7 @@ import { CONSTANTS } from "../common/Testbed";
  import * as path from "path";
  import { FeatureTable, Feature } from "@bentley/imodeljs-common/lib/Render";
  import { Id64 } from "@bentley/bentleyjs-core";
  +import { WebGLTestContext } from "./WebGLTestContext";
  const iModelLocation = path.join(CONSTANTS.IMODELJS_CORE_DIRNAME, "core/backend/lib/test/assets/test.bim");
  @@ -38,7 +39,7 @@ describe("FeatureOverrides tests", () => {
  document.body.appendChild(canvas!);
  before(async () => { // Create a ViewState to load into a Viewport
  - IModelApp.startup();
  + WebGLTestContext.startup();
  imodel = await IModelConnection.openStandalone(iModelLocation);
  spatialView = await imodel.views.load("0x34") as SpatialViewState;
  spatialView.setStandardRotation(StandardViewId.RightIso);
  @@ -46,7 +47,7 @@ describe("FeatureOverrides tests", () => {
  after(async () => {
  if (imodel) await imodel.closeStandalone();
  - IModelApp.shutdown();
  + WebGLTestContext.shutdown();
  });
  it("should create a uniform feature overrides object", () => {
  