Debugger: Fix staticMetaObject extraction with LLDB

When asked for Foo::staticMetaObject, it will find
any *::staticMetaObject. Looking for the mangled name
finds the one we need.

Change-Id: I4508a3c282bc8a46efa011efb73f32cdbf46398c
Reviewed-by: Eike Ziller <eike.ziller@digia.com>