[VM] Remove flutter/flutter patch for 3head, the issue has been fixed…

… upstream

Namely by flutter/flutter#28101

Change-Id: I686927bebffccbb1b575ba488739c38e7de68c9e
Reviewed-on: https://dart-review.googlesource.com/c/93940
Reviewed-by: Martin Kustermann <kustermann@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
Commit-Queue: Martin Kustermann <kustermann@google.com>
Commit-Queue: Siva Annamalai <asiva@google.com>
Auto-Submit: Martin Kustermann <kustermann@google.com>