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

PR-URL: nodejs#45722
Fixes: nodejs#43465
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Paolo Insogna <paolo@cowtech.it>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

Author: sonimadhuri

test/parallel/parallel.status

@@ -40,8 +40,6 @@ test-runner-watch-mode: PASS,FLAKY
 # https://github.com/nodejs/node/issues/42741
 test-http-server-headers-timeout-keepalive: PASS,FLAKY
 test-http-server-request-timeout-keepalive: PASS,FLAKY
-# https://github.com/nodejs/node/issues/43465
-test-http-server-request-timeouts-mixed: PASS,FLAKY
 # https://github.com/nodejs/node/issues/50243
 test-inspector-async-stack-traces-set-interval: PASS, FLAKY