Fix test script attach4.test so that it works with type 1 VFS implementations (no wal). And wal.test so that it work with a small default pager cache size.

FossilOrigin-Name: 29c7b42587000704d61f49badd584ac7040c3d7d

test/wal.test

@@ -1544,6 +1544,7 @@ ifcapable autovacuum {
   } [expr 84 * 1024]
   do_test 24.4 {
     execsql { 
+      PRAGMA cache_size = 200;
       PRAGMA incremental_vacuum;
       PRAGMA wal_checkpoint;
     }