Reduce number of goroutines in TestConcurrentCreateGroups

Currently the number of goroutines created in TestConcurrentCreateGroups is too
large that sometimes the limit of 8192 goroutines of the race detector on
Windows is exceeded. Reducing the number of goroutines may relieve the problem.

Fixes antrea-io#5261.

Signed-off-by: shi0rik0 <anguuan@outlook.com>

pkg/ovs/openflow/ofctrl_bridge_test.go

@@ -122,7 +122,7 @@ func TestConcurrentCreateGroups(t *testing.T) {
 	b := NewOFBridge("test-br", GetMgmtAddress(ovsconfig.DefaultOVSRunDir, "test-br"))
 	b.SwitchConnected(newFakeOFSwitch(b))
 	// Race detector on Windows has limit of 8192 simultaneously alive goroutines.
-	concurrentNum := 8000
+	concurrentNum := 7000
 	var wg sync.WaitGroup
 	for i := 0; i < concurrentNum; i++ {
 		wg.Add(1)