Allow app zygote to keep APK / shared libs open across fork.

It appears that a recent change in ART causes the application APK to be
held open as a file descriptor as soon as the class loader for that
application is instantiated. This creates issues for the application
zygote, which pre-creates the class loader and forks later. For now,
allow the app APK and shared libs to be open as file descriptors when
forking.

Bug: 111434506
Test: atest CtsApptestCases:ServiceTest
Change-Id: I5f3f4fb41a037362b4f0999ddd20402cbe56f025