fdo#75757: remove inheritance to std::map

Change-Id: I26ec60868c7854517b81ade3aec6b7ab29b0aa89
Reviewed-on: https://gerrit.libreoffice.org/12401
Reviewed-by: Takeshi Abe <tabe@fixedpoint.jp>
Tested-by: Takeshi Abe <tabe@fixedpoint.jp>