test: mark test-child-process-pipe-dataflow as flaky

PR-URL: nodejs/node#48334
Reviewed-By: Yagiz Nizipli <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>

Author: MoLow

test/parallel/parallel.status

@@ -17,6 +17,8 @@ test-timers-immediate-queue: PASS,FLAKY
 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
 
 [$system==linux]
 # https://github.com/nodejs/node/issues/46683