Amend ordering of SQL Server tests execution

This is supposed to workaround OOM problems when multiple test instances
are initialized. This seems to be prerequisite if we want to add more
QueryRunner-based tests.

plugin/trino-sqlserver/pom.xml

@@ -15,6 +15,14 @@
 
     <properties>
         <air.main.basedir>${project.parent.basedir}</air.main.basedir>
+
+        <!--
+          Project's default for air.test.parallel is 'methods'. By design, 'classes' makes TestNG run tests from one class in a single thread.
+          As a side effect, it prevents TestNG from initializing multiple test instances upfront, which happens with 'methods'.
+          A potential downside can be long tail single-threaded execution of a single long test class.
+          TODO (https://github.com/trinodb/trino/issues/11294) remove when we upgrade to surefire with https://issues.apache.org/jira/browse/SUREFIRE-1967
+          -->
+        <air.test.parallel>classes</air.test.parallel>
     </properties>
 
     <dependencies>