In some instances, Chrome can apparently fail CDTP calls with "Execution context was destroyed". According to the internet this mostly happens because of navigation events, here it's not clear if this is in response to `stop`-ing the page, or a pre-existing navigation directive interfereing with the stop-ing of the browser. I tried reproducing locally under the assumption that the `Page.stopLoading` might be the cause but got nowhere[^1].

This issue seems extremely infrequent, and in most cases is but a minor annoyance, an error appears on the corresponding build, and that's it.

However if the error occurs during `ChromeBrowser.stop` then the browser is not terminated, which on runbot prevents the docker image from shutting down properly, and leaves zombie builds.

Therefore make `ChromeBrowser.stop` more resilient to errors in the initial section so that we do terminate the browser even if the "graceful CDTP shutdown" fails. While at it, add a fallback to kill the browser if it does not terminate gracefully.

https://runbot.odoo.com/odoo/error/233442

[^1]: and the error only happening in 18.0 and later when `Page.stopLoading` was present long before that makes it likely the proximal cause is in the code being run, especially as all the errors sampled from the builds list are related to pos and the failure are immediately preceded by ongoing HTTP requests