disable GSO and ECN on kernels older than version 5 (#4456)

quic_suite_linux_test.go

@@ -0,0 +1,12 @@
+//go:build linux
+
+package quic
+
+import (
+	"fmt"
+)
+
+func init() {
+	major, minor := kernelVersion()
+	fmt.Printf("Kernel Version: %d.%d\n\n", major, minor)
+}