[C++] Allow creating dictionary array from simple JSON

[asfimport]

Would make writing some tests slightly easier.

Reporter: Antoine Pitrou / @pitrou
Assignee: Antoine Pitrou / @pitrou

Related issues:

• [C++] ArrayFromJSON for dictionary arrays (is duplicated by)

PRs and other links:

• GitHub Pull Request #8309

_{Note: This issue was originally created as ARROW-7372. Please see the migration documentation for further details.}

[asfimport]

Antoine Pitrou / @pitrou:
Issue resolved by pull request 8309
#8309