ConsoleUtilitiesEditor.cs

using UnityEditor;
using System.Reflection;
using System;

public static class ConsoleUtilitiesEditor
{
	[MenuItem("Tools/Clear Console %#c")] // Cmd/Ctrl + Shift + C
	private static void ClearConsoleMenuItem()
	{
		ClearConsole();
	}

	public static void ClearConsole()
	{
#if UNITY_2017_1_OR_NEWER
		Assembly assembly = Assembly.GetAssembly(typeof(SceneView));
		if (assembly != null)
		{
			Type logEntriesType = assembly.GetType("UnityEditor.LogEntries");

			if (logEntriesType != null)
			{
				var clearMethod = logEntriesType.GetMethod("Clear", BindingFlags.Static | BindingFlags.Public);
				clearMethod.Invoke(null, null);
			}
		}
#else
			Assembly assembly = Assembly.GetAssembly(typeof(SceneView));
			if (assembly != null)
			{
				Type logEntriesType = assembly.GetType("UnityEditorInternal.LogEntries");

				if (logEntriesType != null)
				{
					var clearMethod = logEntriesType.GetMethod("Clear", BindingFlags.Static | BindingFlags.Public);
					clearMethod.Invoke(null, null);
				}
			}
#endif
	}
}