test: mark cluster-net-send test flaky on windows

See https://github.com/nodejs/node/issues/3957 for details and examples
failures.

Ref: https://github.com/nodejs/node/issues/3957
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
PR-URL: https://github.com/nodejs/node/pull/4006

test/parallel/parallel.status

@@ -2,18 +2,19 @@ prefix parallel
 
 # To mark a test as flaky, list the test name in the appropriate section
 # below, without ".js", followed by ": PASS,FLAKY". Example:
-# sample-test                       : PASS,FLAKY
+# sample-test                        : PASS,FLAKY
 
 [true] # This section applies to all platforms
 
 [$system==win32]
+test-cluster-net-send                : PASS,FLAKY
 test-tls-ticket-cluster              : PASS,FLAKY
 test-child-process-fork-regr-gh-2847 : PASS,FLAKY
 
 [$system==linux]
-test-http-client-timeout-event    : PASS,FLAKY
-test-child-process-buffering      : PASS,FLAKY
-test-child-process-exit-code      : PASS,FLAKY
+test-http-client-timeout-event       : PASS,FLAKY
+test-child-process-buffering         : PASS,FLAKY
+test-child-process-exit-code         : PASS,FLAKY
 
 [$system==macos]