hash-object: demonstrate a >4GB/LLP64 problem

hash-object: demonstrate a >4GB/LLP64 problem

On LLP64 systems, such as Windows, the size of `long`, `int`, etc. is
only 32 bits (for backward compatibility). Git's use of `unsigned long`
for file memory sizes in many places, rather than size_t, limits the
handling of large files on LLP64 systems (commonly given as `>4GB`).

Provide a minimum test for handling a >4GB file. The `hash-object`
command, with the  `--literally` and without `-w` option avoids
writing the object, either loose or packed. This avoids the code paths
hitting the `bigFileThreshold` config test code, the zlib code, and the
pack code.

Subsequent patches will walk the test's call chain, converting types to
`size_t` (which is larger in LLP64 data models) where appropriate.

Signed-off-by: Philip Oakley <redacted>
Signed-off-by: Johannes Schindelin <redacted>
Signed-off-by: Junio C Hamano <redacted>