grpc-js: Fix a couple of errors from a previous PR

Author: murgatroid99

packages/grpc-js/src/subchannel.ts

@@ -227,8 +227,6 @@ export class Subchannel {
     }
     const previousState = this.connectivityState;
     this.connectivityState = newState;
-    process.nextTick(() => {
-    });
     switch (newState) {
       case ConnectivityState.READY:
         this.stopBackoff();

packages/grpc-js/test/test-global-subchannel-pool.ts

@@ -27,7 +27,7 @@ const protoFile = path.join(__dirname, 'fixtures', 'echo_service.proto');
 const echoService =
     loadProtoFile(protoFile).EchoService as ServiceClientConstructor;
 
-describe.only('Global subchannel pool', () => {
+describe('Global subchannel pool', () => {
   let server: Server;
   let serverPort: number;