Abort for invalid combinations

GraphThreadPoolExecutor will NOT work if user is
trying to use a shared thread pool for just their
data driven tests (or) for all tests (both regular and data driven)
.

So if these combinations are found, abort execution.

testng-core/src/main/java/org/testng/TestNG.java

@@ -1209,9 +1209,11 @@ public List<ISuite> runSuitesLocally() {
     // Create a map with XmlSuite as key and corresponding SuiteRunner as value
     for (XmlSuite xmlSuite : m_suites) {
       if (m_configuration.isShareThreadPoolForDataProviders()) {
+        abortIfUsingGraphThreadPoolExecutor("Shared thread-pool for data providers");
         xmlSuite.setShareThreadPoolForDataProviders(true);
       }
       if (m_configuration.useGlobalThreadPool()) {
+        abortIfUsingGraphThreadPoolExecutor("Global thread-pool");
         xmlSuite.shouldUseGlobalThreadPool(true);
       }
       createSuiteRunners(suiteRunnerMap, xmlSuite);
@@ -1262,6 +1264,13 @@ private static void error(String s) {
     LOGGER.error(s);
   }
 
+  private static void abortIfUsingGraphThreadPoolExecutor(String prefix) {
+    if (RuntimeBehavior.favourCustomThreadPoolExecutor()) {
+      throw new UnsupportedOperationException(
+          prefix + " is NOT COMPATIBLE with TestNG's custom thread pool executor");
+    }
+  }
+
   /**
    * @return the verbose level, checking in order: the verbose level on the suite, the verbose level
    *     on the TestNG object, or 1.