Remove git dependencies from pub-cache

#61487

* Promtoe WidgetTester.ensureVisible

* modify according to tvolkert@

https://github.com/flutter/flutter/issues/61496

The function passes most of its arguments through to
`_DialogRoute`, but it wasn't providing the default
values that `_DialogRoute` was, causing it to override
the defaults will null values.

The Xcode build almost always takes longer than 2 seconds. With the
operation classified as a "fast operation", the Flutter tool will
warn the user that the build is "taking an unexpectedly long time".
This updates the operation to be a "slow operation", which will only
warn the user if it takes 2+ minutes.

Allow configuring the flutter_manifest to support a synthetic package, this is done through flutter: generate: true.

When running pub get, insert a flutter_gen entry into the packages if it does not already exist. This points to .dart_tool/flutter_gen, which can be updated to contain the generated intl sources (But doesn't currently)

Adds an integration test that verifies this code can be run and imported when enabled.

Part of #60914

* Fixing patch for coming breaking change in HttpClientRequest

* Add noSuchMethod() and comment out abort()

* Add ignore: override_on_non_overriding_member

Add document for mouse cursor mapping on Windows and Linux.

* migrate foundation to nullsafety

* address review comments

Enable null safety asserts for web debug mode. This induces runtime asserts at the boundaries between null safe and non-null safe libraries. Adds integration test that validates assertion error is thrown.

#61042

Revert "Reland "Add support for Dart Development Service (DDS) in Flutter Tools (#61276)" (#61395)" (#61498)

This reverts commit f98184e4.

This reverts commit 5b9c6e2b.

This reverts commit 9f4499f4.

For #61407 , we need to be able to find all widgets that of a given type. Previously I experimented with using the type name, but of course this does not handles subtypes. The actual check needs to be an is check.

Since there is no way to convert a String to a Type at runtime for use in this check, we can instead evaluate an expression which assigns a closure to a field. The idea for this was inspired by how the dart devtools adds debug functionality to older versions of flutter.

Since the reload feature is not complete yet, adds an integration test which simulates how it will eventually behave

Implements the flutter config feature for #61407 , but does not implement any of the functionality.

* Improve error reporting for RenderObject visitChildren errors

* Nits and fixes