With `createUnallocatedBox` utility change from #96106 , the TODO for assumed-rank in entry
can simply be lifted and test is added.

The key is that a unallocated assumed-rank descriptor is created with
rank zero in the entry where an assumed-rank dummy from some other entry
do not appear as a dummy (the symbol must still be mapped to some valid
value because the symbol could be used in code that would be unreachable
at runtime, but that the compiler must still generate).

Global with initial value were missing the CUDA data attribute.

The frontend computes the necessary alignment for COMMON blocks but this
information is never carried over to the code generation and can lead to
segfault for COMMON block that requires a non default alignment.

This patch add an optional attribute on fir.global and carries over the
information.

Lower allocatable and pointers specification parts. Nothing special is
required to allocate the descriptor given they are required to be dummy
arguments, however, care must be taken with INTENT(OUT) to use the
runtime to deallocate them (inlined fir.embox + store is not possible).

Enable lowering of assumed-ranks in specification parts under a debug
flag. I am using a debug flag because many cryptic TODOs/issues may be
hit until more support is added. The development should not take too
long, so I want to stay away from the noise of adding an actual
experimental flag to flang-new.

The number of operations dedicated to CUF grew and where all still in
FIR. In order to have a better organization, the CUF operations,
attributes and code is moved into their specific dialect and files. CUF
dialect is tightly coupled with HLFIR/FIR and their types.

The CUF attributes are bundled into their own library since some
HLFIR/FIR operations depend on them and the CUF dialect depends on the
FIR types. Without having the attributes into a separate library there
would be a dependency cycle.

The lowering produces fir.dummy_scope operation if the current
function has dummy arguments. Each hlfir.declare generated
for a dummy argument is then using the result of fir.dummy_scope
as its dummy_scope operand. This is only done for HLFIR.

I was not able to find a reliable way to identify dummy symbols
in `genDeclareSymbol`, so I added a set of registered dummy symbols
that is alive during the variables instantiation for the current
function. The set is initialized during the mapping of the dummy
argument symbols to their MLIR values. It is reset right after
all variables are instantiated - this is done to avoid generating
hlfir.declare operations with dummy_scope for the clones of
the dummy symbols (e.g. this happens with OpenMP privatization).

If this can be done in a cleaner way, please advise.

Lower locals allocation of cuda device, managed and unified variables to
fir.cuda_alloc. Add fir.cuda_free in the function context finalization.

@vzakhari For some reason the PR #90526 has been closed when I merged PR
#90525. Just reopening one.

The corresponding member functions are deprecated.