Reverted moving the IsArm64 property.

Author: dlemstra

src/Magick.NET/Helpers/Runtime.cs

@@ -10,5 +10,7 @@ internal static partial class Runtime
 {
     public static bool Is64Bit { get; } = IntPtr.Size == 8;
 
+    public static bool IsArm64 { get; } = RuntimeInformation.ProcessArchitecture == Architecture.Arm64;
+
     public static bool IsWindows { get; } = RuntimeInformation.IsOSPlatform(OSPlatform.Windows);
 }

tests/Magick.NET.Tests/TestHelpers/TestRuntime.cs

@@ -2,21 +2,20 @@
 // Licensed under the Apache License, Version 2.0.
 
 using System.Runtime.InteropServices;
+using ImageMagick;
 
 namespace Magick.NET.Tests;
 
 internal static class TestRuntime
 {
     public static bool HasFlakyLinuxArm64Result
-        => IsLinux && IsArm64;
+        => IsLinux && Runtime.IsArm64;
 
     public static bool HasFlakyMacOSResult
         => IsMacOS;
 
     public static bool HasFlakyMacOSArm64Result
-        => IsMacOS && IsArm64;
-
-    private static bool IsArm64 { get; } = RuntimeInformation.ProcessArchitecture == Architecture.Arm64;
+        => IsMacOS && Runtime.IsArm64;
 
     private static bool IsLinux { get; } = RuntimeInformation.IsOSPlatform(OSPlatform.Linux);