build: re-enable disabled gesture config test (#16845)

eaf70ca temporarily disabled the gesture
config tests because the blocklist didn't work. Now that the blocklist works on
the framework side, we can re-enable this test again.

Once this PR lands, we can update the SHA on the framework repo and
add the gesture tests to the blocklist.

(cherry picked from commit fa81811)

Author: devversion

src/material/core/gestures/gesture-config.spec.ts

@@ -3,13 +3,7 @@ import {Component} from '@angular/core';
 import {HAMMER_GESTURE_CONFIG} from '@angular/platform-browser';
 import {GestureConfig, MAT_HAMMER_OPTIONS} from './gesture-config';
 
-// TODO(kara): turn these tests back on when Material is using a release
-// of Angular that contains the HammerModule. They need to be turned off
-// for now in order to land https://github.com/angular/angular/pull/32203,
-// which makes Hammer optional (so Material/FW integration tests don't start
-// to fail).
-/* tslint:disable */
-xdescribe('GestureConfig', () => {
+describe('GestureConfig', () => {
   beforeEach(async(() => {
     TestBed.configureTestingModule({
       declarations: [ButtonWithLongpressHander],