fix(table): not clearing some internal references on destroy

`CdkTable` keeps track of various definitions internally in order to render itself, however some of them weren't being cleared on destroy which could lead to memory leaks. These changes add some extra logic to clear the tracked references.

Author: crisbeto

src/cdk/table/table.ts

@@ -447,12 +447,23 @@ export class CdkTable<T> implements AfterContentChecked, CollectionViewer, OnDes
   }
 
   ngOnDestroy() {
-    this._rowOutlet.viewContainer.clear();
-    this._headerRowOutlet.viewContainer.clear();
-    this._footerRowOutlet.viewContainer.clear();
-
-    this._cachedRenderRowsMap.clear();
+    [
+      this._rowOutlet.viewContainer,
+      this._headerRowOutlet.viewContainer,
+      this._footerRowOutlet.viewContainer,
+      this._cachedRenderRowsMap,
+      this._customColumnDefs,
+      this._customRowDefs,
+      this._customHeaderRowDefs,
+      this._customFooterRowDefs,
+      this._columnDefsByName
+    ].forEach(def => {
+      def.clear();
+    });
 
+    this._headerRowDefs = [];
+    this._footerRowDefs = [];
+    this._defaultRowDef = null;
     this._onDestroy.next();
     this._onDestroy.complete();