[C++] Add tests for DayTimeIntervalBuilder

[asfimport]

Reporter: Ben Kietzman / @bkietz

_{Note: This issue was originally created as ARROW-7938. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
[~emkornfield@gmail.com] Do you still want to be assigned this issue?

[asfimport]

Micah Kornfield / @emkornfield:
I took care of this as part of MonthDayNano work, so I think we can leave it assigned to me and I'll update once the PR for that gets merged.

[asfimport]

Todd Farmer / @toddfarmer:
This issue was last updated over 90 days ago, which may be an indication it is no longer being actively worked. To better reflect the current state, the issue is being unassigned. Please feel free to re-take assignment of the issue if it is being actively worked, or if you plan to start that work soon.

[github-actions]

This issue has been marked as stale because it has had no activity in the past 365 days. Please remove the stale label or comment below, or this issue will be closed in 14 days. If this improvement is still desired but has no current owner, please add the 'Status: needs champion' label.

[HyukjinKwon]

I am working on this!

[kou]

Issue resolved by pull request 48709
#48709