test: mark `test-http2-debug` as flaky on LinuxONE

test: mark `test-http2-debug` as flaky on LinuxONE · nodejs/node@007c82f

Original file line number	Diff line number	Diff line change
`@@ -41,6 +41,10 @@ test-esm-loader-hooks-inspect-wait: PASS, FLAKY`
`41`	`41`	`# https://github.com/nodejs/node/issues/54534`
`42`	`42`	`test-runner-run-watch: PASS, FLAKY`
`43`	`43`
	`44`	`+[$system==linux && $arch==s390x]`
	`45`	`+# https://github.com/nodejs/node/issues/58353`
	`46`	`+test-http2-debug: PASS, FLAKY`
	`47`	`+`
`44`	`48`	`[$system==linux \|\| $system==win32]`
`45`	`49`	`# https://github.com/nodejs/node/issues/49605`
`46`	`50`	`test-runner-watch-mode: PASS,FLAKY`