range_tree: use zfs_panic_recover() for partial-overlap remove

zfs_range_tree_remove_impl() used a bare panic() when a segment to be
removed was not completely overlapped by an existing tree entry.  Every
other consistency check in range_tree.c uses zfs_panic_recover(), which
respects the zfs_recover tunable and allows pools with on-disk
corruption to be imported and recovered.  This one call was
inconsistent, making the partial-overlap case unrecoverable regardless
of zfs_recover.

Replace panic() with zfs_panic_recover() so that operators can set
zfs_recover=1 to import a corrupted pool and reclaim data, consistent
with all other range tree error paths.

Related-to: #13483
Reviewed-by: Tony Hutter <hutter2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Clemens Fruhwirth <clemens@endorphin.org>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Closes #18255

Author: clefru

module/zfs/range_tree.c

@@ -539,7 +539,7 @@ zfs_range_tree_remove_impl(zfs_range_tree_t *rt, uint64_t start, uint64_t size,
 	}
 
 	if (!(rstart <= start && rend >= end)) {
-		panic("zfs: rt=%s: removing segment "
+		zfs_panic_recover("zfs: rt=%s: removing segment "
 		    "(offset=%llx size=%llx) not completely overlapped by "
 		    "existing one (offset=%llx size=%llx)",
 		    ZFS_RT_NAME(rt),