fix(tabs): no longer use OnPush

This resolves an issue with ivy where the template content would be
checked out of sync with the tab view. See #15440 for additional
context.

Author: jelbourn

src/material/tabs/tab-body.ts

@@ -108,7 +108,6 @@ export class MatTabBodyPortal extends CdkPortalOutlet implements OnInit, OnDestr
   templateUrl: 'tab-body.html',
   styleUrls: ['tab-body.css'],
   encapsulation: ViewEncapsulation.None,
-  changeDetection: ChangeDetectionStrategy.OnPush,
   animations: [matTabsAnimations.translateTab],
   host: {
     'class': 'mat-tab-body',

src/material/tabs/tab-group.ts

@@ -84,7 +84,6 @@ const _MatTabGroupMixinBase: CanColorCtor & CanDisableRippleCtor & typeof MatTab
   templateUrl: 'tab-group.html',
   styleUrls: ['tab-group.css'],
   encapsulation: ViewEncapsulation.None,
-  changeDetection: ChangeDetectionStrategy.OnPush,
   inputs: ['color', 'disableRipple'],
   host: {
     'class': 'mat-tab-group',

src/material/tabs/tab-header.ts

@@ -48,7 +48,6 @@ import {MatPaginatedTabHeader} from './paginated-tab-header';
   inputs: ['selectedIndex'],
   outputs: ['selectFocusedIndex', 'indexFocused'],
   encapsulation: ViewEncapsulation.None,
-  changeDetection: ChangeDetectionStrategy.OnPush,
   host: {
     'class': 'mat-tab-header',
     '[class.mat-tab-header-pagination-controls-enabled]': '_showPaginationControls',

src/material/tabs/tab.ts

@@ -38,7 +38,6 @@ const _MatTabMixinBase: CanDisableCtor & typeof MatTabBase =
   selector: 'mat-tab',
   templateUrl: 'tab.html',
   inputs: ['disabled'],
-  changeDetection: ChangeDetectionStrategy.OnPush,
   encapsulation: ViewEncapsulation.None,
   exportAs: 'matTab',
 })