Add dump support for empty views

[daxmawal]

Fix issue #25
There is also a draft proposed PR in Kokkos Core to fix this.

Fix overview

Before, the dump path trusted the size reported by the Kokkos allocation hook and used it as the number of bytes to copy from p_data.

That is unsafe because p_data points to the user-data region after the Kokkos allocation header, while the reported size can be larger than the bytes that are actually available from that pointer.

For a non-empty view, the layout looks like this:

allocation base                                      allocation end
|                                                    |
v                                                    v
+--------------------------+-------------------------+
| Kokkos allocation header | user data bytes         |
+--------------------------+-------------------------+
                           ^
                           |
                         p_data

For an empty view, p_data point at the end of the allocation:

allocation base             allocation end
|                           |
v                           v
+---------------------------+
| Kokkos allocation header  |
+---------------------------+
                            ^
                            |
                          p_data

The fix computes the real allocation bounds first, then validates the byte range before copying:

available = allocation_end - p_data

if available >= reported_size:
    copied size = reported_size
else:
    copied size = 0

The dump now stores both values:
size: number of user-data bytes that are safe to copy
reported_size: size reported by the Kokkos allocation hook