httpConnAutoCloseDelayedOnUpgrade and httpServerDeleteRequestHasBody are flaky

[andreubotella]

https://github.com/denoland/deno/runs/4361438674?check_suite_focus=true#step:35:2107

These tests have pending async ops in commits for #12862. That PR changes the clamping of timers from 4ms to 0, which affects the delay before the ops sanitizer runs, but as pointed out by @lucacasonato in #12862 (comment), if the pending ops take longer than one event loop turn to resolve, that is a bug.

[bnoordhuis]

https://github.com/denoland/deno/runs/4443957712?check_suite_focus=true - now happening on the main branch.