fix(runtime): async load order improvements; guarantee parent / child order contract

[johnjenkins]

What is the current behavior?

GitHub Issue Number: #6636 (and more)

For any tree of Stencil components, regardless of which output is used, this should be the order:

• connectedCallback fires top-down - never before the nearest Stencil ancestor's has fully completed.
• componentWillLoad fires top-down, after descendants have connected - never before every already-present Stencil descendant's connectedCallback has fired. (The core bug: component's child initial timing leads to unexpected behavior #6636 fix.)
• componentDidLoad fires bottom-up — never before all descendants' componentDidLoads have

This should be true no-matter if using the lazy loader, standalone components or the standalone auto-loader .. at present this is not the case. Network latency (for example) can cause this lifecycle of events to fire out-of-order.

What is the new behavior?

The contract is enforced

Documentation

Does this introduce a breaking change?

• Yes
• No

Not strictly - but could be a change in expectation if someone is currently relying on a particular order.

Testing

Other information