With this change,

	pesi.set(onerror_continue, true);

can be used to restore behavior from before varnish-cache 7.3.

See pesi.set() documentation for details.

The test case is a modified version of the one by Geoff Simmons posted
in https://github.com/varnishcache/varnish-cache/issues/4053#issuecomment-1936000064