Explicitly require root privs for tests requiring it

These tests currently require root privs to interact with netd:
  resolv_integration_test
  libnetdbpf_test
  netd_unit_test
  netd_integration_test

Bug: 134891412
Test: atest
Change-Id: I3e286fd7e7603e30b4f4d655fe311c35e05fbc78
diff --git a/server/Android.bp b/server/Android.bp
index dbb5372..bf2c1dd 100644
--- a/server/Android.bp
+++ b/server/Android.bp
@@ -207,6 +207,7 @@
     name: "netd_unit_test",
     defaults: ["netd_defaults"],
     test_suites: ["device-tests"],
+    require_root: true,
     include_dirs: [
         "system/netd/include",
         "system/netd/server/binder",