Don't use es6 api in platform api

src/vs/platform/remote/common/tunnel.ts

@@ -18,7 +18,7 @@ export interface RemoteTunnel {
 export interface ITunnelService {
 	_serviceBrand: undefined;
 
-	readonly tunnels: Promise<Iterable<RemoteTunnel>>;
+	readonly tunnels: Promise<readonly RemoteTunnel[]>;
 
 	openTunnel(remotePort: number): Promise<RemoteTunnel> | undefined;
 }

src/vs/platform/remote/common/tunnelService.ts

@@ -8,7 +8,7 @@ import { ITunnelService, RemoteTunnel } from 'vs/platform/remote/common/tunnel';
 export class NoOpTunnelService implements ITunnelService {
 	_serviceBrand: undefined;
 
-	public readonly tunnels: Promise<Iterable<RemoteTunnel>> = Promise.resolve([]);
+	public readonly tunnels: Promise<readonly RemoteTunnel[]> = Promise.resolve([]);
 
 	openTunnel(_remotePort: number): Promise<RemoteTunnel> | undefined {
 		return undefined;

src/vs/workbench/services/remote/node/tunnelService.ts

@@ -97,7 +97,7 @@ export class TunnelService implements ITunnelService {
 		@ILogService private readonly logService: ILogService,
 	) { }
 
-	public get tunnels(): Promise<Iterable<RemoteTunnel>> {
+	public get tunnels(): Promise<readonly RemoteTunnel[]> {
 		return Promise.all(Array.from(this._tunnels.values()).map(x => x.value));
 	}