Range analysis did not request sorted output from the storage engine,
which cause partitioned handlers to process one partition at a time
while reading key prefixes in ascending order, causing values to be 
missed. Fixed by always requesting sorted order during range analysis.
This fix is introduced in 6.0 by the fix for bug no 41136.

mysql-test/r/group_min_max.result:
  Bug#44821: Test result.
mysql-test/t/group_min_max.test:
  Bug#44821: Test case
sql/opt_range.cc:
  Bug#44821: Fix.