...where ItemHolder1 apparently leaks the items ever since

> commit ef2c49c9
> Author: Rüdiger Timm <rt@openoffice.org>
> Date:   Fri Nov 11 07:50:10 2005 +0000
>
>     INTEGRATION: CWS perform06 (1.6.60); FILE MERGED
>     2005/11/07 13:32:40 as 1.6.60.2: #i56589# dont cache GlobalEventConfig() inside ItemHolder1^... combination of static pointer and WeakImplHelper cant not work
>     2005/10/25 08:04:02 as 1.6.60.1: #i56589# hold config items alive till office die

That started to cause problems when 78a6ce17
"DELETEZ->std::unique_ptr in toolkit,unotools" now stopped to leak the global

  static std::unique_ptr<SvtLoadSaveOptions_Impl> pOptions;

in unotools/source/config/saveopt.cxx when any SvtSaveOptions instances are
leaked, so that at least PythonTest_pyuno_pytests_testcollections started to
fail in ASan builds now when that global pOptions is destroyed at exit.

I don't see a good reason for that ItemHolder1::holdConfigItem stuff here, so
lets try and drop it from SvtSaveOptions at least.

Change-Id: I6d44708fc4e2e5dfafaa9bfe8f3fa2f854ae0952
Reviewed-on: https://gerrit.libreoffice.org/46726Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>