In PRIF revision 0.8, the representation of `prif_coarray_handle` was
changed. This PR updates this representation for this type and updates
the MIFOpConversion pass for the relevant operations.
Fixes issue #214080
A minor fix has been made to the deallocation to ensure that, on the
Flang side, the variable is properly deallocated, since previously the
deallocation was only performed at the `coarray_handle` level.
(cherry picked from commit 066dfd519323589e89847e65a40d4a9836f61188)