test: remove test-http2-client-upload as flaky

The test has not failed in quite some time (as far as I can tell) on CI.
Optimistically removing it.

Refs: #29889

PR-URL: #36496
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

test/parallel/parallel.status

@@ -8,8 +8,6 @@ prefix parallel
 
 [$system==win32]
 # https://github.com/nodejs/node/issues/20750
-test-http2-client-upload: PASS,FLAKY
-# https://github.com/nodejs/node/issues/20750
 test-http2-client-upload-reject: PASS,FLAKY
 # https://github.com/nodejs/node/issues/30847
 test-http2-compat-client-upload-reject: PASS,FLAKY