libext2fs: fix tests that set LARGE_FILE

libext2fs: fix tests that set LARGE_FILE

For each site where we test for a large file (> 2GB) and set the
LARGE_FILE feature, use a helper function to make the size test
consistent with the test that's in e2fsck.  This fixes the fsck
complaints when we try to create a 2GB journal (not so hard with 64k
block size) and fixes the incorrect test in fileio.c.

Reviewed-by: Zheng Liu <wenqing.lz@taobao.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>