Close lua state when exiting on a runtime error (#1487)

* Close lua state when exiting on a runtime error

* This change allows calling the garbage collector before exiting the
  application for a cleaner shutdown.
* Components like the shared memory object on #1486 will have a better
  chance at destroying no longer needed resources.

* Overriden os.exit to always close the state

* Allow setting close param on os.exit override

* Simplified the os.exit override a bit more

Co-authored-by: Guldoman <giulio.lettieri@gmail.com>

---------

Co-authored-by: Guldoman <giulio.lettieri@gmail.com>

src/main.c

@@ -253,6 +253,10 @@ init_lua:
 
   const char *init_lite_code = \
     "local core\n"
+    "local os_exit = os.exit\n"
+    "os.exit = function(code, close)\n"
+    "  os_exit(code, close == nil and true or close)\n"
+    "end\n"
     "xpcall(function()\n"
     "  local match = require('utf8extra').match\n"
     "  HOME = os.getenv('" LITE_OS_HOME "')\n"