[Process] Fix process merge in 2.3

Handles should be read and closed after `proc_close` is called.
merged branch romainneutron/process-merge-2.3 (PR #8990)

This PR was merged into the 2.3 branch.

Discussion
----------

[Process][2.3] Fix process merge in 2.3

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| License       | MIT

Handles should be read and closed after `proc_close` is called. (this follows merge of #8983)

Commits
-------

19fef77 [Process] Fix process merge in 2.3