In several of the Playwright APIs, falsey values were not handled correctly. This changeset adds tests (and some fixes):
- route.continue: If options.postData was the empty string, the continue failed to override the post data.
- page.post (application/json with options.data: false|''|0|null): Raw falsey values were getting dropped (i.e. you can't do the equivalent of curl --header application/json … -d 'false'). This has been fixed with most values across all browsers, but an additional fix is needed for 'null' which the channel serializer treats extra specially.
- testInfo.attach: This didn't get reported as an error when options.path was the empty string, but should have been.
#11413 (and its fix#11414) inspired this search as they are the same
class of bug.
