Describe the bug

The order of panels within InspectorControls is non-deterministic and changes depending on whether you are editing an existing block or a freshly inserted one.

To reproduce
Steps to reproduce the behavior:

1. Copy and paste ES5 example from https://developer.wordpress.org/block-editor/developers/filters/block-filters/#editor-blockedit in the console
2. Insert a new video block and select a video right away
3. Notice the custom panel at the top of the block toolbar
4. De-select block and select it again
5. Notice that the custom panel now comes after the Video Settings panel

Expected behavior
The order should always be the same so that it can be deterministic.

Otherwise this not only confuses users, it also makes it harder to target individual controls via CSS to hide them (because there is still no API for that)

Screenshots

Freshly inserted block:

After selecting the block again:

Desktop (please complete the following information):
Chrome 74 on macOS Mojave

Additional context

Gutenberg 5.7 RC 1