[Windows] Improve performance of ContentPanel.EnsureBorderPath

[MartyIX]

Description of Change

This PR is a simple performance improvement for ContentPanel on Windows.

The main change is in the 3rd commit (5056720), previous commits fix code style.

Performance comparison

Speedscope comparing main and this PR using testing code (main, PR):

How to repeat:

cd src/Controls/samples/Controls.Sample.Sandbox
dotnet publish -f net8.0-windows10.0.19041.0 -c Release -p:PublishReadyToRun=false -p:WindowsPackageType=None
dotnet trace collect --format speedscope -- .\bin\Release\net8.0-windows10.0.19041.0\win10-x64\publish\Maui.Controls.Sample.Sandbox.exe

and click Batch Add Borders button FIVE times.

Issues Fixed

Contributes to #21087

[MartyIX]

This is the main change.

[jsuarezruiz]

Also invoked from

maui/src/Core/src/Handlers/Border/BorderHandler.Windows.cs

Line 24 in bfc9876

handler.PlatformView.EnsureBorderPath();

[MartyIX]

Yes. I believe one cannot use containsCheck = false there though so I did not do it.

If it is not what you meant, please clarify.

[dotnet-policy-service]

Hey there @MartyIX! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[jsuarezruiz]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[jsuarezruiz]

Could you update again the Speedscope comparison screenshot?

[MartyIX]

Here is the original one:

Or do you mean a new one?

[jsuarezruiz]

Also invoked from

maui/src/Core/src/Handlers/Border/BorderHandler.Windows.cs

Line 24 in bfc9876

handler.PlatformView.EnsureBorderPath();