Revert "ios: Disable ARQuickLook tests on iOS12/Xcode12b4."

This reverts commit 2d01e3cc.

Reason for revert: testInvocations isn't supported by test runner.

Original change's description:
> ios: Disable ARQuickLook tests on iOS12/Xcode12b4.
> 
> XCUIElement queries used in ARQuickLook are broken on Xcode 12 beta 4
> when running on the iOS 12 simulator.  Disable until Xcode is fixed.
> 
> Bug: 1114202
> Change-Id: Ib16458ee93e6821b5520cbd791e3ba8e6beccfe4
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2341220
> Auto-Submit: Justin Cohen <justincohen@chromium.org>
> Commit-Queue: Rohit Rao <rohitrao@chromium.org>
> Reviewed-by: Rohit Rao <rohitrao@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#795982}

TBR=rohitrao@chromium.org,justincohen@chromium.org

Change-Id: Ic1ea153414e47bc0a3867dcf609a3313bd877623
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1114202
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2343551Reviewed-by: Justin Cohen <justincohen@chromium.org>
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#796175}

ios/chrome/browser/ui/download/ar_quick_look_egtest.mm

@@ -84,19 +84,6 @@ std::unique_ptr<net::test_server::HttpResponse> GetResponse(
 
 @implementation ARQuickLookEGTest
 
-#if defined(__IPHONE_14_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_14_0
-// TODO(crbug.com/1114202): The XCUIElement queries in this test are broken on
-// Xcode 12 beta 4 when running on the iOS 12 simulator.  Disable until Xcode
-// is fixed.
-+ (NSArray*)testInvocations {
-  if (@available(iOS 13, *)) {
-    return [super testInvocations];
-  } else {
-    return @[];
-  }
-}
-#endif
-
 - (void)setUp {
   [super setUp];