The SQL query was built using the clauses compiled when querying for
top-level comments. But in cases where the top-level comment query
results are already in the cache, the SQL clauses are not built, and
so are unavailable for `fill_descendants()`. Instead, we call
`get_comments()`, using modified versions of the parameters passed
to the main `WP_Comment_Query` class.
Props Akeif, Rarst for testing.
Fixes#37696.
git-svn-id: https://develop.svn.wordpress.org/trunk@38446 602fd350-edb4-49c9-b593-d223f7449a82
2fc4e48d07