emmc_optimized means stable_inodes

If the emmc_optimized filesystem flag is set, then like
inlinecrypt_optimized, we have to ensure that stable_inodes is set
on the filesystem.

Bug: 144046242
Test: Cuttlefish, ext4: set the flag in fstab, check for the
    stable_inodes flag using tunefs -l
Change-Id: Id7f906564457c240ddf6677dd536698881385385