Print guest stack trace on invalid memory access (#1407)

* Print guest stack trace on invalid memory access

* Improve XML docs

Ryujinx.Cpu/InvalidAccessHandler.cs

@@ -0,0 +1,9 @@
+namespace Ryujinx.Cpu
+{
+    /// <summary>
+    /// Function that handles a invalid memory access from the emulated CPU.
+    /// </summary>
+    /// <param name="va">Virtual address of the invalid region that is being accessed</param>
+    /// <returns>True if the invalid access should be ignored, false otherwise</returns>
+    public delegate bool InvalidAccessHandler(ulong va);
+}