Update parallel setting for Windows in integration test

Current parallel setting to 25 is too high especially for Windows. Every node will
have about 8-10 disks are being attached and fomatted around the same
time. For Windows Disk format time could reach about 4 mins which makes
the whole pod start time exceeds 5 mins and timeout.

Add parallel parameter into test. By default it sets to 10 to any
platform. If it does not work well for Windows, we can adjust in the
test script by passing parallel parameter.

Author: jingxu97

test/k8s-integration/main.go

@@ -70,6 +70,7 @@ var (
 	testFocus     = flag.String("test-focus", "", "test focus for Kubernetes e2e")
 
 	useKubeTest2 = flag.Bool("use-kubetest2", false, "use kubetest2 to run e2e tests")
+	parallel     = flag.Int("parallel", 10, "the number of parallel tests setting for ginkgo parallelism")
 )
 
 const (
@@ -99,6 +100,7 @@ type testParameters struct {
 	clusterVersion       string
 	nodeVersion          string
 	imageType            string
+	parallel             int
 }
 
 func init() {
@@ -200,6 +202,7 @@ func handle() error {
 		deploymentStrategy:  *deploymentStrat,
 		useGKEManagedDriver: *useGKEManagedDriver,
 		imageType:           *imageType,
+		parallel:            *parallel,
 	}
 
 	goPath, ok := os.LookupEnv("GOPATH")
@@ -663,8 +666,7 @@ func runTestsWithConfig(testParams *testParameters, testConfigArg, reportPrefix
 	}
 	kubeTest2Args = append(kubeTest2Args, fmt.Sprintf("--focus-regex=%s", testParams.testFocus))
 	kubeTest2Args = append(kubeTest2Args, fmt.Sprintf("--skip-regex=%s", testParams.testSkip))
-	// kubetest uses 25 as default value for ginkgo parallelism (--nodes).
-	kubeTest2Args = append(kubeTest2Args, "--parallel=25")
+	kubeTest2Args = append(kubeTest2Args, fmt.Sprintf("--parallel=%d", testParams.parallel))
 	kubeTest2Args = append(kubeTest2Args, fmt.Sprintf("--test-args=%s %s", testConfigArg, windowsArgs))
 
 	if kubetestDumpDir != "" {