[flang] Copy attributes and flags onto host-assoc symbols

As with use-associated symbols, copy the attributes and flags from the
original symbol onto host-associated symbols when they are created.

This was showing up as an error on a deallocate of a host-associated
name. We reported an error because the symbol didn't have the POINTER
or ALLOCATABLE attribute.

Differential Revision: https://reviews.llvm.org/D85763