Fix summary report count of tests run by test.dart when tests are run on a browser.

tools/testing/dart/test_suite.dart

Index: tools/testing/dart/test_suite.dart
diff --git a/tools/testing/dart/test_suite.dart b/tools/testing/dart/test_suite.dart
index a7255dfec83eef2e62c2cd3a9106b8172ec25be2..ac5b802cf4e1d2c0ecfd5d0af3dfedf75523168a 100644
--- a/tools/testing/dart/test_suite.dart
+++ b/tools/testing/dart/test_suite.dart
@@ -392,6 +392,10 @@ class StandardTestSuite implements TestSuite {
     if (configuration['report']) {
       // Tests with multiple VMOptions are counted more than once.
       for (var dummy in optionsFromFile["vmOptions"]) {
+        if (TestUtils.isBrowserRuntime(configuration['runtime']) &&
+            optionsFromFile['isMultitest']) {
+          break;  // Browser tests skip multitests.
+        }
         SummaryReport.add(expectations);
       }
     }