This patch contains several changes to `deallocate_size.pass.cpp`:
1. `static_cast`-ing some parameters to `size_t` to avoid narrowing.
2. Changing the type of loop variable `i` to `unsigned int` avoid
signedness mismatch with the constructor parameter.
3. Separately counting allocations and deallocations in variables
`allocated_` and `deallocated_`, and changing their type to `uint64_t`.
4. Avoiding `assert`-ing count of allocations when a `basic_string` is
allocated, just `assert`-ing after destruction instead.
73b092ff33