Remove spammy "Network distribution disabled" message from default config

R=machenbach@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/1279613005

Cr-Commit-Position: refs/heads/master@{#30094}

tools/run-tests.py

@@ -668,7 +668,8 @@ def Execute(arch, mode, args, options, suites, workspace):
 
   run_networked = not options.no_network
   if not run_networked:
-    print("Network distribution disabled, running tests locally.")
+    if verbose_output:
+      print("Network distribution disabled, running tests locally.")
   elif utils.GuessOS() != "linux":
     print("Network distribution is only supported on Linux, sorry!")
     run_networked = False