Update code paths that assumed "unsigned long" was long enough for
"size_t".
* js/objects-larger-than-4gb-on-windows:
ci: run expensive tests on push builds to integration branches
t5608: mark >4GB tests as EXPENSIVE
test-tool synthesize: add precomputed SHA-256 pack for 4 GiB + 1
test-tool synthesize: precompute pack for 4 GiB + 1
test-tool synthesize: use the unsafe hash for speed
t5608: add regression test for >4GB object clone
test-tool: add a helper to synthesize large packfiles
delta, packfile: use size_t for delta header sizes
odb, packfile: use size_t for streaming object sizes
git-zlib: handle data streams larger than 4GB
index-pack, unpack-objects: use size_t for object size