[flang] Lower elemental and transformational clean-up in HLFIR

[flang] Lower elemental and transformational clean-up in HLFIR

In lowering to hlfir, no clean-up was added yet for
the created hlfir.elemental. Add  the needed hlfir.destroy.

Regarding transformational lowering, clean-ups were created because
they are lowered in memory, but this is inconvenient because this
prevented lowering to hlfir from "moving" the created variable to
an expression. Add a new entry point in IntrinsicCall.h that keeps
track of whether or not the returned storage needs to be deallocated,
but does not insert the deallocation in the StatementContext.
This allows using the newly added hlfir.as_expr "move" aspect to be
used and save creating a copy.

Depends on D141839

Reviewed By: clementval

Differential Revision: https://reviews.llvm.org/D141841