Change the FormBrowser behavior of "Pressing ESC":

Change the FormBrowser behavior of "Pressing ESC":
The old behavior is: if press ESC, it will exit the whole Formset.
The new behavior is: if press ESC, it will return to the parent Form; if current Form is the root Form of a FormSet, it will exit the whole FormSet.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9359 6f19259b-4bc3-4df7-8a09-765794883524