pgsql: Second thoughts on TOAST decompression.

Second thoughts on TOAST decompression.

On detecting a corrupted match tag, pglz_decompress() should just
summarily return -1. Breaking out of the loop, as I did in dfc797730,
doesn't quite guarantee that will happen. Also, we can use
unlikely() on that check, just in case it helps.

Backpatch to v13, like the previous patch.

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/fd2997565c6f66837440dd57f5e52b56aa964d14

Modified Files
--------------
src/common/pg_lzcompress.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)