BUG: date_range breaks with tz-aware start/end dates and closed intervals #12409
- [X] closes #12409 
- [X] tests added / passed
- [X] passes `git diff upstream/master | flake8 --diff`
- [ ] whatsnew entry - not added since this fixes a pre-release bug

do comparison for closed intervals on UTC basis prior to tz conversion
added tests for date_range covering case of tz-aware start/end dates with closed ranges

right, but can find where it was changed and add this issue number 
 put this issue number in the whatsnew next to #11804 
 lgtm. squash; ping when ready.
 good to go
 can you add the test from the issue as well. I am not convinced your tests actually replicate the issue.
 added more tests covering original issue
 ok, looks good. ping when green.
 good to go
 thanks!
