Context: dotnet#12130
Context: https://github.com/angelru/CvSlowJittering
Context: https://github.com/jonathanpeppers/lols

Testing a customer sample and my LOLs per second sample, I could see a
lot of time (5.1%) spent in `PrepareForTextViewArrange()`:

    1.01s (5.1%) microsoft.maui!Microsoft.Maui.ViewHandlerExtensions.PrepareForTextViewArrange(Microsoft.Maui.IViewHandler,Microsoft.Maui
    635.99ms (3.2%) mono.android!Android.Views.View.get_Context()

Most of the time is spent just calling `View.Context` to be able to do:

    internal static int MakeMeasureSpecExact(this Context context, double size)
    {
        // Convert to a native size to create the spec for measuring
        var deviceSize = (int)context!.ToPixels(size);
        return MeasureSpecMode.Exactly.MakeMeasureSpec(deviceSize);
    }

In eea91d3, I added an overload for `ToPixels()` that allows you to
get the same value with an `Android.Views.View` -- avoiding the need
to call `View.Context`.

So we can instead do:

    internal static int MakeMeasureSpecExact(this PlatformView view, double size)
    {
        // Convert to a native size to create the spec for measuring
        var deviceSize = (int)view.ToPixels(size);
        return MeasureSpecMode.Exactly.MakeMeasureSpec(deviceSize);
    }

After these changes, it seems to be ~2.7% better:

    420.68ms (2.4%) microsoft.maui!Microsoft.Maui.ViewHandlerExtensions.PrepareForTextViewArrange(Microsoft.Maui.IViewHandler,Microsoft.Maui

The `View.Context` call is now completely gone.