The only way I could find to complete coverage for _http_common.js is to
use semi-private (exposed but probably shouldn't be) handlers to get the
state into something weird. With the if-condition being checked (see
Refs) commented out, I get this result from this test:
```
node:_http_common:140
if (len > 0 && !stream._dumped) {
^
TypeError: Cannot read property '_dumped' of null
at HTTPParser.parserOnBody (node:_http_common:140:26)
```
With the check in place, the test passes without an error. Seems like
quite the edge case, but I'm going to assume it's there for a reason.
Refs: https://coverage.nodejs.org/coverage-b560645d6b0a4bed/lib/_http_common.js.html#L137
PR-URL: https://github.com/nodejs/node/pull/37958
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
