Bug 999053: [FTU Ping] Handle multisim situations more gracefully when collecting network info. r=fabrice

Conflicts:

	apps/system/test/unit/ftu_ping_test.js
Merge pull request #20106 from marshall/bug995434_ftuPingSimLocked_master

Bug 999053: [FTU Ping] Handle multisim situations more gracefully when collecting network info