test: skip test-child-process-pipe-dataflow.js on Windows

This is constantly failing on Windows now that the CI is never green
there. To give CI at least some green space, mark it as SKIP, because
we've been practically ignoring the failure for months anyway, and
will probably just continue doing that.

PR-URL: nodejs#49563
Refs: nodejs#48300
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

test/parallel/parallel.status

@@ -12,7 +12,7 @@ test-crypto-keygen: PASS,FLAKY
 # https://github.com/nodejs/node/issues/41201
 test-fs-rmdir-recursive: PASS, FLAKY
 # https://github.com/nodejs/node/issues/48300
-test-child-process-pipe-dataflow: PASS, FLAKY
+test-child-process-pipe-dataflow: SKIP
 test-child-process-stdio-reuse-readable-stdio: PASS, FLAKY
 
 # Windows on ARM