Enable DEFENSIVE mode by default for tests. This requires lots of case of

turning DEFENSIVE off in order to dodgy things to the database for testing
purposes.  No all of those cases are yet handled, so "make test" does not run
to completion.

FossilOrigin-Name: a1d6c6712c3304fd736077432c8c180692cf7d79be7f3a073510b6dab0eb951f

ext/rtree/rtree8.test

@@ -101,7 +101,9 @@ do_test rtree8-1.3.5 {
 #
 populate_t1 50
 do_execsql_test rtree8-2.1.1 { SELECT max(nodeno) FROM t1_node } {5}
+sqlite3_db_config db DEFENSIVE 0
 do_execsql_test rtree8-2.1.2 { DELETE FROM t1_node } {}
+sqlite3_db_config db DEFENSIVE 1
 for {set i 1} {$i <= 50} {incr i} {
   do_catchsql_test rtree8-2.1.3.$i { 
     SELECT * FROM t1 WHERE id = $i 
@@ -121,9 +123,11 @@ do_execsql_test rtree8-2.1.6 {
 
 
 populate_t1 50
+sqlite3_db_config db DEFENSIVE 0
 do_execsql_test rtree8-2.2.1 {
   DELETE FROM t1_parent
 } {}
+sqlite3_db_config db DEFENSIVE 1
 do_catchsql_test rtree8-2.2.2 {
   DELETE FROM t1 WHERE id=25
 } {1 {database disk image is malformed}}