Btrfs: add tests for find_lock_delalloc_range

So both Liu and I made huge messes of find_lock_delalloc_range trying to fix stuff, me first by fixing extent size, then him by fixing something I broke and then me again telling him to fix it a different way. So this is obviously a candidate for some testing. This patch adds a pseudo fs so we can allocate fake inodes for tests that need an inode or pages. Then it addes a bunch of tests to make sure find_lock_delalloc_range is acting the way it is supposed to. With this patch and all of our previous patches to find_lock_delalloc_range I am sure it is working as expected now. Thanks,

JBJosef Bacik committed 13 years ago