This reverts commit d92b3b40.

Date picker tests have been flaky on Windows for a long time, and repeatedly require restarting of bots. In the interest of productivity, disabling them on Windows.

Related to #19696

Fixed several layout issues with the material date picker. Mostly just removed hard coded sizes to allow the grid view to scroll instead of overflowing.

* some space formattings

* always use blocks in if-else if a block is used

* format spaces in for and while

* allow multiline if conditions

* fix missing space

* the onStart callback will report the location of the pointer where it wins the gesture arena by default instead of the pointer down location. Fixes all tests related to changing this default value.

* Force DatePicker value to stay within firstDate and lastDate upon year change

* updated per review feedback

This reverts commit 08538f91.

* Adds start behavior option to the drag gesture recognizer and makes it the default option when a drag gesture recognizer is created. Also fixes all the tests to work correctly with the new default behavior.

* Future<void> main

* Future<void>.delayed

* prefer_void_to_Null

* address review comments

* enable lint unnecessary_new

* fix tests

* fix tests

* fix tests

It was causing problems rolling Flutter into Fuchsia

* re-enable lint unnecessary_const

* remove trailling whitespaces

* remove unnecessary const (after merge)

This reverts commit cc1cf13e.

* Chevrons in month picker are semi-transparent when the month is scrolled

* Added type missing annotation

* Set text direction in semantics along with Directionality

* update tests for the extra SemanticsNode

New a11y traversal:

- sort direct sibling SemanticsNodes only
- use new sorting algorithm
- implement RTL
- test semantics in traversal order by default
- add AppBar traversal test
- breaking: remove nextNodeId/previousNodeId from the framework
- breaking: remove DebugSemanticsDumpOrder.geometricOrder

Semantics object support for edge triggered semantics 

* a11y: remove SemanticsSortOrder; sort locally only; semanticsOwner post-test check

* update accessibility test framework

- default nextNodeId/previousNodeId to -1
- stop treating null as opt-out from value testing
- add `id`, `TestSemantics.root`, and `tags` to the suggested code in the TestSemantics failure message
- fix a small bug with raw string escaping
- update all tests accordingly

* fix sortKey doc

* prefer const over final

`RenderSemanticsGestureHandler` is no longer a semantics boundary, which allows us to correctly mark disabled buttons as disabled without having their semantics size and semantics node id change unexpectedly.

Fixes https://github.com/flutter/flutter/issues/12589.
Fixes https://github.com/flutter/flutter/issues/11991.
See also https://github.com/flutter/flutter/issues/11993.

This change also required some refactoring to how we deal with `twoPaneSemantics` scrolling as it previously relied on `RenderSemanticsGestureHandler` being a semantics boundary. This should also make the underlying logic easier to understand.

In addition, the following minor changes are included in this PR:
* Removal of orphaned and unused `SemanticsConfiguration.isMergingDescendantsIntoOneNode`.
* Logic optimizations for `markNeedsSemanticsUpdate` .
* Fix for edge case where `MergeSemantics` failed to merge semantics.
* Use of emojis to better indicate leaf merging in the printed semantics tree.
* Better assert message for adding invisible child semantics nodes.
* Make some semantics tests robuster by not relying on creation order of SemanticsNode ids across test boundaries.

Fixes https://github.com/flutter/flutter/issues/13943.

to align with `SemanticsAction` and other enum-like types.

* IconButton is a button, semantically

* fix datepicker test

* make date picker accessible

* make test file lookup location-independent

* address some comments

* always wrap in IgnorePointer

* no bitmasks for flags and actions

* recommend List<*>

* formatYear

* localize date picker

* tests

* clean-ups

* address comments

* Let the initial date picker mode be selectable

* Doc for enum

* Add a test

* Add a comment for test

* actually decouple test from setup state

Fixes https://github.com/flutter/flutter/issues/10917