Revert "Add browsertests for tab sharing UI views."

This reverts commit 916c54c5.

Reason for revert:
abDragTabSharingUIViewsBrowserTest.DragTab and
TabDragTabSharingUIViewsBrowserTest.DragSharedTab fail on linux-chromeos-rel
https://ci.chromium.org/p/chromium/builders/ci/linux-chromeos-rel

Original change's description:
> Add browsertests for tab sharing UI views.
> 
> Add tests to verify tab sharing UI elements: infobars, contents border
> and tab sharing indicator.
> 
> Bug: 996722
> Change-Id: I5fa5ec7e4a48a66c1ba9b08ff76b84a105961352
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1847287
> Reviewed-by: Guido Urdaneta <guidou@chromium.org>
> Commit-Queue: Marina Ciocea <marinaciocea@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#707368}

TBR=guidou@chromium.org,marinaciocea@chromium.org

Change-Id: I3e000bbd82d3fe3f78684d200cb2c10b4171328e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 996722
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1869116Reviewed-by: Lan Wei <lanwei@chromium.org>
Commit-Queue: Lan Wei <lanwei@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707395}

chrome/test/BUILD.gn

@@ -5642,7 +5642,6 @@ if (!is_android) {
         "../browser/ui/views/passwords/password_bubble_interactive_uitest.cc",
         "../browser/ui/views/sad_tab_view_interactive_uitest.cc",
         "../browser/ui/views/status_icons/status_tray_state_changer_interactive_uitest_win.cc",
-        "../browser/ui/views/tab_sharing/tab_sharing_ui_views_browsertest.cc",
         "../browser/ui/views/tabs/tab_drag_controller_interactive_uitest.cc",
         "../browser/ui/views/tabs/tab_drag_controller_interactive_uitest.h",
         "../browser/ui/views/tabs/tab_hover_card_bubble_view_interactive_uitest.cc",