Address of SymPy-Function `address_of`

Some CUDA functions (like atomic_add) require pointers to data. This PR adds a SymPy function representing the C address-of operator (&).

I tried to trigger cse to show a problem related to this function (dummy variables were not typed correctly as pointer). I'll include the fix in a follow-up PR.

changed title from Address of function to Address of {+SymPy-Function address_of+}

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added 2 commits

• 3e8137af - Add _print_address_of for address_of to cbackend
• 42cac737 - Add test for `address_of`

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added 2 commits

• b62d1107 - Add _print_address_of for address_of to cbackend
• eef42a24 - Add test for `address_of`

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added 2 commits

• fda4e1e5 - Add _print_address_of for address_of to cbackend
• 2210e7a5 - Add test for `address_of`

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added 2 commits

• de250f5a - Add _print_address_of for address_of to cbackend
• 9f79445e - Add test for `address_of`

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merged

mentioned in commit a30d5181