Repository: moby/moby (language: go)

Issue:
Workflows for testing on Microsoft Windows
### Description

I see that moby uses [busybox-w32](https://github.com/rmyorston/busybox-w32) to perform tests on Microsoft Windows. Downloads of the required busybox-w32 binaries from my [website](https://frippery.org/files/busybox) have increased substantially over the past few months. They now account for over 75% of download bandwidth, with most of that occurring between 10:00-11:00 UTC when the windows-2019 workflow is scheduled to run.

Some suggestions:
- Don't ship the windows-2019 workflow with the scheduled run enabled. Although GitHub ask users to understand the consequences of enabling workflows I'm sure many don't realise that windows-2019 will be run every day.
- Review the workflows to determine if it's really necessary to download busybox-w32 fourteen times on every run.
- Bundle the BusyBox binary.
- Use a caching server. The [Julia](https://github.com/JuliaLang/julia) project also uses busybox-w32 for testing. They direct their downloads to a caching server on their own infrastructure, only falling back to my website if that fails.
- Use something other than busybox-w32 to provide Unix-like utilities on Microsoft Windows.

Also, please note that [contrib/busybox/Dockerfile](https://github.com/moby/moby/blob/master/contrib/busybox/Dockerfile) is configured to use version FRP-3329-gcf0fa4d13 of busybox-w32. This is now the oldest binary on the website. It will be removed when it turns three years old on 9th January 2023. Switching to a more recent version before then is recommended.


Discussion / hints:

Fix patch:
diff --git a/contrib/busybox/Dockerfile b/contrib/busybox/Dockerfile
index b57c09a724e23..51a27e0b7338a 100644
--- a/contrib/busybox/Dockerfile
+++ b/contrib/busybox/Dockerfile
@@ -19,7 +19,7 @@ FROM ${WINDOWS_BASE_IMAGE}:${WINDOWS_BASE_IMAGE_TAG}
 RUN mkdir C:\tmp && mkdir C:\bin
 ARG BUSYBOX_VERSION
 ARG BUSYBOX_SHA256SUM
-ADD https://frippery.org/files/busybox/busybox-w32-${BUSYBOX_VERSION}.exe /bin/busybox.exe
+ADD https://github.com/moby/busybox/releases/download/${BUSYBOX_VERSION}/busybox-w32-${BUSYBOX_VERSION}.exe /bin/busybox.exe
 RUN powershell \
     if ((Get-FileHash -Path /bin/busybox.exe -Algorithm SHA256).Hash -ne $Env:BUSYBOX_SHA256SUM) { \
         Throw \"Checksum validation failed\" \


Test patch: