Add recovery flag to reformat /data

For 16K dev options, we might need to reformat /data partition as ext4
before enabling the feature. Add necessary support to recovery.

Test: Trigger reboot with --wipe_data --reformat_data=ext4, make sure
/data is reformatted with ext4 on next boot
Bug: 293313353

Change-Id: I3cb67a62635a2df578472cd48cf6d2f5e04b5f82