Flush the error log before exit

Currently, some logs can be missing when a fatal error occurs (especially GuestBrokeExecutionException).

This MR attempts to flush logs to console and file before process exit.

src/Ryujinx/Program.cs

@@ -272,6 +272,7 @@ namespace Ryujinx.Ava
 
             if (isTerminating)
             {
+                Logger.Flush();
                 Exit();
             }
         }