* Revert "Roll Dart SDK from 094c9024373c to 2ea89ef8f6de (1 revision) (#26030)"

This reverts commit 0d62a560.

* Revert "Roll Dart SDK from 04e55dad908d to 094c9024373c (1 revision) (#26027)"

This reverts commit 06cbf1e0.

* Revert "Roll Dart SDK from b4210cc43086 to 04e55dad908d (2 revisions) (#26020)"

This reverts commit d1a11828.

* Revert "Roll Dart SDK from 86c749398b3a to b4210cc43086 (2 revisions) (#26006)"

This reverts commit 3ffb8efc.

* Revert "Roll Dart SDK from b8f4018535fa to 86c749398b3a (16 revisions) (#25999)"

This reverts commit a712ffe2.

The Windows registry is structured as a hierarchy of named keys, each of
which may contain a set of named values of various datatypes.
RegistryKey objects own the underlying HKEY handle and ensure cleanup at
or prior to destruction.

This adds a RegistryKey class that does automatic resource management
for registry keys and provides convenience functions for accessing keys
and navigating the key hierarchy.

This is library code to be used in uwptool, which adds an adb-like
helper tool for install, uninstall, and launch of UWP applications for
Windows platforms.

See: https://github.com/flutter/flutter/issues/81756

This offers a small improvement in performance in cases where the input
is a raw char* or wchar_t* string due to not having to perform an
implicit conversion to std::string/std::wstring.

Code cleanup covered by existing tests, which already use raw C strings.

Command-line argument parsing is valuable even in the absence of the
rest of FML's functionality.

This is pre-factoring for uwptool, which adds an adb-like helper tool
for install, uninstall, and launch of UWP applications for Windows
platforms.

See: https://github.com/flutter/flutter/issues/81756

String conversion between UTF-8 and UTF-16 encodings is useful even in
the absence of other common Windows functionality.

This is pre-factoring for uwptool, which adds an adb-like helper tool
for install, uninstall, and launch of UWP applications for Windows
platforms.

See: https://github.com/flutter/flutter/issues/81756

We now build against a specific Windows SDK rather than whatever happens
to be installed on the host machine.

This also rolls the buildroot to include change
https://github.com/flutter/buildroot/pull/448, which generates the WinRT
headers from the CIPD Windows SDK.

This also rolls an updated version of cppwinrt that includes supports
for long paths.

This also re-enables the UWP builder.

Currently, the licenses are copied into the bucket just before
uploading it. Copying the licenses is definitely more about "building"
the bucket than it is about "processing the CIPD package", but
concretely, some tools complain if the license files arent there, and
I'd like to be able to use the cipd tool to upload the bucket
directly.
Co-authored-by: NHunter Freyer <hjfreyer@google.com>

Current recommended build methods may not trigger this issue, but
while trying different options, building flutter for the first time, I
noticed a build error because `defines` was assigned twice.

If building with both options is ever supported, I think this
fixes the error.

Ensure that AutoIsolateShutdown drops its reference to the DartIsolate on the intended task runner (#25899)