RippleMethodFinder2 now has a MultiMap for the fTypeToMethod field
because with Generics it is possible to implement more than one method
in a super interface

Change-Id: I187127fae2dc2d6439a795bef915109875ca1eca
Signed-off-by: Nikolay Metchev <nikolaymetchev@gmail.com>
Signed-off-by: Jeff Johnston <jjohnstn@redhat.com>
Reviewed-on: https://git.eclipse.org/r/c/jdt/eclipse.jdt.ui/+/70037
Tested-by: JDT Bot <jdt-bot@eclipse.org>