PR78273 fix count to work with partitioning function

PR78273 fix count to work with partitioning function

	PR libstdc++/78273
	* include/bits/stl_map.h (map::count<_Kt>(const _Kt&)): Don't assume
	the heterogeneous comparison can only find one match.
	* include/bits/stl_set.h (set::count<_Kt>(const _Kt&)): Likewise.
	* testsuite/23_containers/map/operations/2.cc: Test count works with
	comparison function that just partitions rather than sorting.
	* testsuite/23_containers/set/operations/2.cc: Likewise.

From-SVN: r244317