fix(zone.js): don't rely on global node typings outside of node/ directory (#31783)

PR Close #31783

packages/zone.js/lib/zone.ts

@@ -675,6 +675,12 @@ 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'];