fix(zone.js): remove global declaration

Close angular#37531

Remove `global` declaration in `zone.ts` to avoid compile error when
upgrade to `@types/node` v14.0.5. Since the new type of global become
`Global` and not compatible with `zone.ts` declaration.

packages/zone.js/lib/zone.ts

@@ -674,12 +674,6 @@ type AmbientZone = Zone;
 /** @internal */
 type AmbientZoneDelegate = ZoneDelegate;
 
-// CommonJS / Node have global context exposed as "global" variable.
-// This code should run in a Browser, so we don't want to include the whole node.d.ts
-// typings for this compilation unit.
-// We'll just fake the global "global" var for now.
-declare var global: NodeJS.Global;
-
 const Zone: ZoneType = (function(global: any) {
   const performance: {mark(name: string): void; measure(name: string, label: string): void;} =
       global['performance'];
@@ -1440,4 +1434,5 @@ const Zone: ZoneType = (function(global: any) {
 
   performanceMeasure('Zone', 'Zone');
   return global['Zone'] = Zone;
-})(typeof window !== 'undefined' && window || typeof self !== 'undefined' && self || global);
+})(typeof window !== 'undefined' && window || typeof self !== 'undefined' && self ||
+   typeof global !== 'undefined' && global);

packages/zone.js/package.json

@@ -19,7 +19,7 @@
     "test": "test"
   },
   "devDependencies": {
-    "@types/node": "^10.9.4",
+    "@types/node": "^14.0.5",
     "domino": "2.1.2",
     "jest": "^25.1.0",
     "mocha": "^3.1.2",

packages/zone.js/test/common/zone.spec.ts

@@ -343,7 +343,7 @@ describe('Zone', function() {
 
         const ZoneAwarePromise = global.Promise;
         try {
-          global.Promise = WrongPromise;
+          (global as any).Promise = WrongPromise;
           expect(Zone.assertZonePatched()).toThrow();
         } finally {
           // restore it.