[R] Repair map_batches()

[asfimport]

The experimental map_batches() function is broken. The one test for it has not been failing only because it calls the min() function which had no binding and thus triggered abandon_ship() to throw a warning and pull the data into R, preempting the error that would have happened later.

Reporter: Will Jones / @wjones127
Assignee: Will Jones / @wjones127

Related issues:

• [R] experimental map_batches cannot find columns (relates to)
• [R] Refactor do_exec_plan to return a RecordBatchReader (relates to)
• [R][Compute] ExecPlan_run should return RecordBatchReader instead of Table (depends upon)

PRs and other links:

• GitHub Pull Request #11894

_{Note: This issue was originally created as ARROW-14029. Please see the migration documentation for further details.}

[asfimport]

Ian Cook / @ianmcook:
@nealrichardson  do you think this is critical for 6.0.0?

[asfimport]

Neal Richardson / @nealrichardson:
No, but I've left it in scope in case I can squeeze it in after ARROW-14008 merges. If not, I'll bump it.

[asfimport]

Jonathan Keane / @jonkeane:
Issue resolved by pull request 11894
#11894