Fix apparent temporary debugging leftover

Change-Id: I3277a341137b1b404ad9839431b5cc39a88fcbe1
Reviewed-on: https://gerrit.libreoffice.org/68425
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

compilerplugins/clang/simplifybool.cxx

@@ -8,7 +8,6 @@
  */
 
 #include <cassert>
-#include <iostream>
 
 #include "plugin.hxx"
 #include "clang/AST/CXXInheritance.h"