f2fs: introduce FAULT_BLKADDR_CONSISTENCE

We will encounter below inconsistent status when FAULT_BLKADDR type
fault injection is on.

Info: checkpoint state = d6 :  nat_bits crc fsck compacted_summary orphan_inodes sudden-power-off
[ASSERT] (fsck_chk_inode_blk:1254)  --> ino: 0x1c100 has i_blocks: 000000c0, but has 191 blocks
[FIX] (fsck_chk_inode_blk:1260)  --> [0x1c100] i_blocks=0x000000c0 -> 0xbf
[FIX] (fsck_chk_inode_blk:1269)  --> [0x1c100] i_compr_blocks=0x00000026 -> 0x27
[ASSERT] (fsck_chk_inode_blk:1254)  --> ino: 0x1cadb has i_blocks: 0000002f, but has 46 blocks
[FIX] (fsck_chk_inode_blk:1260)  --> [0x1cadb] i_blocks=0x0000002f -> 0x2e
[FIX] (fsck_chk_inode_blk:1269)  --> [0x1cadb] i_compr_blocks=0x00000011 -> 0x12
[ASSERT] (fsck_chk_inode_blk:1254)  --> ino: 0x1c62c has i_blocks: 00000002, but has 1 blocks
[FIX] (fsck_chk_inode_blk:1260)  --> [0x1c62c] i_blocks=0x00000002 -> 0x1

After we inject fault into f2fs_is_valid_blkaddr() during truncation,
a) it missed to increase @nr_free or @valid_blocks
b) it can cause in blkaddr leak in truncated dnode
Which may cause inconsistent status.

This patch separates FAULT_BLKADDR_CONSISTENCE from FAULT_BLKADDR,
and rename FAULT_BLKADDR to FAULT_BLKADDR_VALIDITY
so that we can:
a) use FAULT_BLKADDR_CONSISTENCE in f2fs_truncate_data_blocks_range()
to simulate inconsistent issue independently, then it can verify fsck
repair flow.
b) FAULT_BLKADDR_VALIDITY fault will not cause any inconsistent status,
we can just use it to check error path handling in kernel side.

Reviewed-by: Daeho Jeong <daehojeong@google.com>
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>