[#28899] DocDB: Disable object locking for TestSchemaVersionMismatch

Summary:
TestSchemaVersionMismatch expects schema version mismatch errors amidst processing of DDLs, most of which are eliminated with object locking. Hence, disabled the feature for the test.
Jira: DB-18622

Test Plan:
Jenkins

Enabled object locking by default, and ran the following
```
./yb_build.sh --java-test 'org.yb.pgsql.TestSchemaVersionMismatch#testBasic'
```

Reviewers: amitanand, rthallam

Reviewed By: rthallam

Subscribers: ybase

Differential Revision: https://phorge.dev.yugabyte.com/D47238

Author: basavaraj29

java/yb-pgsql/src/test/java/org/yb/pgsql/TestSchemaVersionMismatch.java

@@ -22,6 +22,7 @@
 import java.sql.Statement;
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
+import java.util.Map;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
 import org.junit.Test;
@@ -55,6 +56,16 @@ public class TestSchemaVersionMismatch extends BasePgSQLTest {
   private static final String updateSqlWithPlaceholder = String.format(updateSqlTemplate, "?");
   private static final String updateSqlWithUuid = String.format(updateSqlTemplate, "'" + uuid + "'");
 
+  @Override
+  protected Map<String, String> getTServerFlags() {
+    Map<String, String> flagMap = super.getTServerFlags();
+    // The test expects schema version mismatch errors admist processing of DDLs, most of which
+    // are eliminated with object locking. Hence, disable the feature for the test.
+    flagMap.put("enable_object_locking_for_table_locks", "false");
+    flagMap.put("allowed_preview_flags_csv", "enable_object_locking_for_table_locks");
+    return flagMap;
+  }
+
   /**
    * Helper method to setup the test table with initial data.
    */