Support passing multiple res folders

Some projects have multiple resources folders. Now they can call this
script with multiple `-r` flag and pass multiple resources folders.

Bug: 259156628
Test: from packages/apps/Car/SystemUI run python3 ../systemlibs/tools/rro/verify-overlayable.py -r res -r res-keyguard -e res/values/overlayable.xml -o res/values/overlayable.xml
Change-Id: I50a1af5e37bf61f75ecd5f1d8da44cc7a9809b7a
2 files changed