Codechange: add tests for GS <-> AdminPort JSON conversion (#11252)

While at it, fix a bug where booleans were made integers.

src/script/api/script_admin.hpp

@@ -36,7 +36,7 @@ public:
 	static bool Send(void *table);
 #endif /* DOXYGEN_API */
 
-private:
+protected:
 	/**
 	 * Convert a Squirrel structure into a JSON string.
 	 * @param vm The VM to operate on.

src/script/api/script_event_types.cpp

@@ -222,11 +222,11 @@ const char *ScriptEventAdminPort::ReadValue(HSQUIRRELVM vm, const char *p)
 	SKIP_EMPTY(p);
 
 	if (strncmp(p, "false", 5) == 0) {
-		sq_pushinteger(vm, 0);
+		sq_pushbool(vm, 0);
 		return p + 5;
 	}
 	if (strncmp(p, "true", 4) == 0) {
-		sq_pushinteger(vm, 1);
+		sq_pushbool(vm, 1);
 		return p + 4;
 	}
 	if (strncmp(p, "null", 4) == 0) {

src/script/api/script_object.hpp

@@ -44,6 +44,7 @@ typedef bool (ScriptAsyncModeProc)();
 class ScriptObject : public SimpleCountedObject {
 friend class ScriptInstance;
 friend class ScriptController;
+friend class TestScriptController;
 protected:
 	/**
 	 * A class that handles the current active instance. By instantiating it at