Allow @BeforeMethod when whole test suite single-threaded

Allow `@BeforeMethod` and `@AfterMethod` on non-single-threaded test
classes when the whole suite is marked as such.

presto-testng-services/src/main/java/io/prestosql/testng/services/ReportMultiThreadedBeforeOrAfterMethod.java

@@ -19,6 +19,8 @@
 import org.testng.annotations.AfterMethod;
 import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.Test;
+import org.testng.xml.XmlSuite.ParallelMode;
+import org.testng.xml.XmlTest;
 
 import java.lang.reflect.Method;
 
@@ -33,6 +35,10 @@ public class ReportMultiThreadedBeforeOrAfterMethod
     public void onBeforeClass(ITestClass testClass)
     {
         try {
+            if (!isParallel(testClass.getXmlTest())) {
+                return;
+            }
+
             reportMultiThreadedBeforeOrAfterMethod(testClass.getRealClass());
         }
         catch (RuntimeException | Error e) {
@@ -44,6 +50,16 @@ public void onBeforeClass(ITestClass testClass)
         }
     }
 
+    private boolean isParallel(XmlTest xmlTest)
+    {
+        if (xmlTest.getThreadCount() == 1) {
+            return false;
+        }
+
+        ParallelMode parallel = xmlTest.getParallel();
+        return parallel.isParallel();
+    }
+
     @VisibleForTesting
     static void reportMultiThreadedBeforeOrAfterMethod(Class<?> testClass)
     {