test: move test-http-server-request-timeouts-mixed

Test was moved to sequential a while back.

PR-URL: #54841
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: LiviaMedeiros <livia@cirno.name>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

Author: jasnell

test/parallel/parallel.status

@@ -40,8 +40,6 @@ test-http2-socket-close: PASS, FLAKY
 [$system==win32 && $arch==arm64]
 
 [$system==linux]
-# https://github.com/nodejs/node/issues/43465
-test-http-server-request-timeouts-mixed: PASS, FLAKY
 # https://github.com/nodejs/node/issues/54803
 test-performance-function: PASS, FLAKY
 # https://github.com/nodejs/node/issues/54346