Currently, we create `forward_aggregates` inside a function that
returns the result of a future lambda that captures these aggregates
by reference. As a result, the aggregates may be destructed before
the lambda finishes, resulting in a heap use-after-free.
To prolong the lifetime of these aggregates, we cannot use a move
capture, because the lambda is wrapped in a with_thread_if_needed()
call on these aggregates. Instead, we fix this by wrapping the
entire return statement in a do_with().
Fixes#12528Closes#12533
(cherry picked from commit 5f45b32bfa)