Strict Null Checks, Builder Removal, Formatting (#4849)

* remove builder; more null checks

* null checks

* formatting

* wip

* fix dropdown themeing

* formatting

* formatting

* fix tests

* update what files are checked

* add code to help refresh bad nodes

src/sql/base/browser/ui/panel/tab.component.ts

@@ -2,6 +2,7 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *  Licensed under the Source EULA. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
+
 import { Component, Input, ContentChild, OnDestroy, TemplateRef, ChangeDetectorRef, forwardRef, Inject } from '@angular/core';
 
 import { Action } from 'vs/base/common/actions';