vlib: enable more satnitized memleak detection runs without false positives on the CI (#23200)

vlib/db/sqlite/parent_child_test.v

@@ -20,7 +20,7 @@ struct Baby {
 }
 
 fn test_main() {
-	db := sqlite.connect(':memory:')!
+	mut db := sqlite.connect(':memory:')!
 
 	sql db {
 		create table Parent
@@ -80,4 +80,6 @@ fn test_main() {
 	assert parent[0].children[0].id == 1
 	assert parent[0].children[1].id == 2
 	assert parent[0].children.len == 2
+
+	db.close()!
 }

vlib/db/sqlite/sqlite_comptime_field_test.v

@@ -22,7 +22,7 @@ fn records_by_field[T](db sqlite.DB, fieldname string, value string) ![]T {
 }
 
 fn test_main() {
-	db := sqlite.connect(':memory:')!
+	mut db := sqlite.connect(':memory:')!
 	sql db {
 		create table Blog
 	}!
@@ -40,4 +40,5 @@ fn test_main() {
 		return
 	}
 	assert rows.len == 1
+	db.close()!
 }

vlib/db/sqlite/sqlite_test.v

@@ -11,7 +11,7 @@ pub:
 type Content = []u8 | string
 
 struct Host {
-pub:
+pub mut:
 	db Connection
 }
 
@@ -92,7 +92,8 @@ fn test_can_access_sqlite_result_consts() {
 }
 
 fn test_alias_db() {
-	create_host(sqlite.connect(':memory:')!)!
+	mut host := create_host(sqlite.connect(':memory:')!)!
+	host.db.close()!
 	assert true
 }
 
@@ -110,7 +111,9 @@ fn test_exec_param_many() {
 		'Sam',
 	]) or {
 		assert err.code() == 19 // constraint failure
+		db.close()!
 		return
 	}
+	db.close()!
 	assert false
 }