hash-object: add a >4GB/LLP64 test case using filtered input

hash-object: add a >4GB/LLP64 test case using filtered input

To verify that the `clean` side of the `clean`/`smudge` filter code is
correct with regards to LLP64 (read: to ensure that `size_t` is used
instead of `unsigned long`), here is a test case using a trivial filter,
specifically _not_ writing anything to the object store to limit the
scope of the test case.

As in previous commits, the `big` file from previous test cases is
reused if available, to save setup time, otherwise re-generated.

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