Run engine-server fixture tests with NODE_ENV=production

[nolanlawson]

I'm noticing that if I run the fixture tests in prod mode, I get different results than dev mode. This seems partially due to some dev-only accessors defined here:

lwc/packages/@lwc/engine-core/src/framework/base-bridge-element.ts

Line 111 in 2b678bb

function createAccessorThatWarns(propName: string) {

This is causing issues with global HTML properties/attributes in particular, but there seem to be some problems with outerHTML as well.

PoC: b890165

[git2gus]

This issue has been linked to a new work item: W-17592100