fix strict null

src/vs/platform/instantiation/common/descriptors.ts

@@ -11,7 +11,7 @@ export class SyncDescriptor<T> {
 	readonly staticArguments: any[];
 	readonly supportsDelayedInstantiation: boolean;
 
-	constructor(ctor: new (...args: any[]) => T, staticArguments: any[] = [], supportsDelayedInstantiation?: boolean) {
+	constructor(ctor: new (...args: any[]) => T, staticArguments: any[] = [], supportsDelayedInstantiation: boolean = false) {
 		this.ctor = ctor;
 		this.staticArguments = staticArguments;
 		this.supportsDelayedInstantiation = supportsDelayedInstantiation;