Revert "fix(tabs): Add role to mat-tab-nav-bar and mat-tab-link" (#11657)

Material nav-tabs intentionally behaves as a nav + anchor

src/lib/tabs/tab-nav-bar/tab-nav-bar.html

@@ -1,4 +1,5 @@
-<div class="mat-tab-links" (cdkObserveContent)="_alignInkBar()" role="tablist">
+<div class="mat-tab-links" (cdkObserveContent)="_alignInkBar()">
   <ng-content></ng-content>
   <mat-ink-bar></mat-ink-bar>
 </div>
+

src/lib/tabs/tab-nav-bar/tab-nav-bar.spec.ts

@@ -16,7 +16,6 @@ describe('MatTabNavBar', () => {
       imports: [MatTabsModule],
       declarations: [
         SimpleTabNavBarTestApp,
-        TabLink,
         TabLinkWithNgIf,
         TabLinkWithTabIndexBinding,
         TabLinkWithNativeTabindexAttr,
@@ -274,16 +273,6 @@ describe('MatTabNavBar', () => {
 
     expect(tabLink.tabIndex).toBe(3, 'Expected the tabIndex to be have been set to 3.');
   });
-
-  it('should set role on tablist and tab', () => {
-    const fixture = TestBed.createComponent(TabLink);
-    fixture.detectChanges();
-
-    const tabList = fixture.debugElement.query(By.css('.mat-tab-links'));
-    expect(tabList.nativeElement.getAttribute('role')).toEqual('tablist');
-    const tabLinkElement = tabList.query(By.directive(MatTabLink)).nativeElement;
-    expect(tabLinkElement.getAttribute('role')).toEqual('tab');
-  });
 });
 
 @Component({
@@ -312,15 +301,6 @@ class SimpleTabNavBarTestApp {
   activeIndex = 0;
 }
 
-@Component({
-  template: `
-    <nav mat-tab-nav-bar>
-      <a mat-tab-link role="willbeoverridden">Link</a>
-    </nav>
-  `
-})
-class TabLink {}
-
 @Component({
   template: `
     <nav mat-tab-nav-bar>

src/lib/tabs/tab-nav-bar/tab-nav-bar.ts

@@ -172,7 +172,6 @@ export const _MatTabLinkMixinBase =
   inputs: ['disabled', 'disableRipple', 'tabIndex'],
   host: {
     'class': 'mat-tab-link',
-    'role': 'tab',
     '[attr.aria-disabled]': 'disabled.toString()',
     '[attr.tabIndex]': 'tabIndex',
     '[class.mat-tab-disabled]': 'disabled',