[BZ #22469]
* localedata/locales/pl_PL (LC_COLLATE): Use “copy "iso14651_t1"”
and implement the collation rules for pl from CLDR on top of that.
* Makefile: Add pl_PL.UTF-8 to test-input and to the list
of locales to be built for testing.
* pl_PL.UTF-8.in: New file with test data to test the Polish sorting.