[FIX] web: avoid warning during qweb tests

One of the qweb tests checks that in a t-set @t-value takes priority
over body contents. However this construct also triggers a warning
when invoked.

Mock out `window.console` during qweb tests, this suppresses that
warning.

addons/web/static/tests/helpers/utils.js

@@ -208,3 +208,8 @@ export async function legacyExtraNextTick() {
 export function mockDownload(cb) {
     patchWithCleanup(download, { _download: cb });
 }
+
+export const hushConsole = Object.create(null);
+for(const propName of Object.keys(window.console)) {
+    hushConsole[propName] = () => {}
+}

addons/web/static/tests/legacy/qweb_tests.js

@@ -2,6 +2,7 @@ odoo.define('web.qweb_tests', function (require) {
 "use strict";
 
 var qwebPath = '/web/static/lib/qweb/';
+const {hushConsole} = require('@web/../tests/helpers/utils');
 
 function trim(s) {
     return s.replace(/(^\s+|\s+$)/g, '');
@@ -63,7 +64,13 @@ function loadTest(assert, template, context) {
     return prom;
 }
 
-QUnit.module('QWeb', {}, function () {
+QUnit.module('QWeb', {
+    before() {
+        this.oldConsole = window.console;
+        window.console = hushConsole;
+    },
+    after() {window.console = this.oldConsole;}
+}, function () {
     QUnit.test('Output', function (assert) {
         loadTest(assert, 'qweb-test-output.xml');
     });