UnsupportedAppUsage - support implicit member signatures

Allows the signature of implicit members, i.e. members that are added
by the compiler, e.g. enum values() and valueOf(String) methods or
default constructors to be specified per class. The UnsupportedAppUsage
can now be repeated on a class so as to specify multiple implicit
members.

Bug: 119861512
Test: atest class2greylisttest, m -j20 framework
Change-Id: I73c8402e9c2053e3a04ef0ff8875ce446593ec8f