[Context] Move switchToOriginalStack() into module and add DBG statement

emper/Context.cpp

 // SPDX-License-Identifier: LGPL-3.0-or-later
-// Copyright © 2020 Florian Schmaus
+// Copyright © 2020-2022 Florian Schmaus
 #include "Context.hpp"
 
 #include <ostream>
@@ -22,3 +22,11 @@ auto operator<<(std::ostream& strm, const Context& context) -> std::ostream& {
 			 << "]";
 	return strm;
 }
+
+[[noreturn]] void Context::switchToOriginalStack() {
+	// Can't use new context hook to communicate the context to free.
+	lastContextBeforeReturningToOriginalStack = currentContext;
+	currentContext = nullptr;
+	DBG("Switchting to original stack " << &originalStack << " from " << currentContext);
+	switch_and_load_context(&originalStack);
+}