test: skip irrelevant test on Windows

Skip test-cluster-disconnect-handles on Windows.

PR-URL: https://github.com/nodejs/node/pull/12261
Ref: https://github.com/nodejs/node/pull/12197#issuecomment-292228866
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

test/known_issues/known_issues.status

@@ -8,6 +8,7 @@ prefix known_issues
 
 [$system==win32]
 test-stdout-buffer-flush-on-exit: SKIP
+test-cluster-disconnect-handles: SKIP
 
 [$system==linux]