syscalls/fallocate04: add 'FALLOC_FL_INSERT_RANGE' test-case

Check that it can insert space in the middle of the file.
Verify new size and file's content. The flag is available
since Linux 4.1. Supported FS: XFS(4.1+) & ext4(4.2+).

Also fix test04() if number of blocks more than 3.

Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Reviewed-by: Cyril Hrubis <chrubis@suse.cz>
2 files changed