test: remove test-gc-http-client-timeout from flaky list

PR-URL: nodejs/node#43971
Refs: nodejs/node#43949
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>

test/sequential/sequential.status

@@ -32,8 +32,6 @@ test-tls-psk-client: PASS, FLAKY
 test-tls-securepair-client: PASS, FLAKY
 
 [$arch==arm]
-# https://github.com/nodejs/node/issues/43638
-test-gc-http-client-timeout: PASS,FLAKY
 
 [$arch==s390x]
 # https://github.com/nodejs/node/issues/41286