Run object destructors before clearing autoload handler

Our request shutdown procedure cleared the autoload handler
before running destructors of any remaining objects. This was causing
fatals when some of those destructors tried to use a
class/function/constant that hadn't already been autoloaded.

hphp/runtime/vm/bytecode.cpp

@@ -7248,7 +7248,6 @@ void VMExecutionContext::requestInit() {
 
 void VMExecutionContext::requestExit() {
   treadmillSharedVars();
-  destructObjects();
   syncGdbState();
   tx()->requestExit();
   Transl::Translator::clearTranslator();