Fixes https://github.com/flutter/flutter/issues/149625
This adds a new constructor CupertinoNavigationBar.large for the large style navigation bar. CupertinoSliverNavigationBar enables dynamically changing between the smaller and larger layouts for native iOS headers in response to scrolling, this change makes it possible to configure the static navigation bar in one style or the other.
* Add magnification of CupertinoSliverNavigationBar large title
* Fix padding in maximum scale computation
* Apply magnification by using RenderBox
* Do not pass key to the superclass constructor
* Use `clampDouble` instead of `clamp` extension method
* Remove trailing whitespaces to make linter happy
* Name test variables more precisely
* Move transform computation to `performLayout` and implement `hitTestChildren`
* Address comments
* Address comments
* Address comments
* Update comment about scale
* Fix hit-testing
* Fix hit-testing again
* Make linter happy
* Implement magnifying without using LayoutBuilder
* Remove trailing spaces
* Add hit-testing of the large title
* Remove whitespaces
* Fix scale computation and some tests
* Fix remaining tests
* Refactor and fix comments
* Update comments