SONAR-12271 require SQ 7.9 installed to upgrade to 8.0 and later

drop IT for module upgrade since 7.9 has no module
fix UpgradeTest:
 - explicitly fail if run on H2
 - fix all URL tests which were victimes of false negatives

server/sonar-db-migration/src/main/java/org/sonar/server/platform/db/migration/version/DatabaseVersion.java

@@ -30,7 +30,7 @@ public class DatabaseVersion {
    * versions must be previously upgraded to LTS version.
    * Note that the value can't be less than current LTS version.
    */
-  public static final long MIN_UPGRADE_VERSION = 1_830;
+  public static final long MIN_UPGRADE_VERSION = 2_800;
 
   private final MigrationSteps migrationSteps;
   private final MigrationHistory migrationHistory;