LU-13547 tests: remove ea_inode from mkfs MDT options

LU-13547 tests: remove ea_inode from mkfs MDT options

The large_dir and ea_inode is enabled by default when MDTs
are formatted.  Thus, remove 'ea_inode' and 'large_dir'
from the mkfs options in the test-framework.

Add a test to make sure that these MDT features are enabled
by default.

Signed-off-by: James Nunez <jnunez@whamcloud.com>
Change-Id: I1b3f1bee7e0c091f8fffc9da0e769eed921dac8f
Reviewed-on: https://review.whamcloud.com/38582
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Li Dongyang <dongyangli@ddn.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>