checksum: test failures on 32bit systems

[hannesm]

https://ocaml.ci.dev/github/robur-coop/utcp/commit/8d0f4ca0e561a27eab3f4f1cd085ab077e005ab0/variant/debian-12-5.1_x86_32_opam-2.1

│ [FAIL] Checksum 0 simple. │
└──────────────────────────────────────────────────────────────────────────────┘
ASSERT simple
FAIL simple

Expected: 39786' Received: 24831'

Called from unknown location
Called from unknown location

Logs saved to `/src/_build/default/test/_build/_tests/TCP tests/Checksum.000.output'.
──────────────────────────────────────────────────────────────────────────────

┌──────────────────────────────────────────────────────────────────────────────┐
│ [FAIL] Checksum 1 data1. │
└──────────────────────────────────────────────────────────────────────────────┘
ASSERT data1
FAIL data1

Expected: 39529' Received: 24319'

Called from unknown location
Called from unknown location

Logs saved to `/src/_build/default/test/_build/_tests/TCP tests/Checksum.001.output'.
──────────────────────────────────────────────────────────────────────────────

┌──────────────────────────────────────────────────────────────────────────────┐
│ [FAIL] Checksum 2 data2. │
└──────────────────────────────────────────────────────────────────────────────┘
ASSERT data2
FAIL data2

Expected: 39526' Received: 24319'

Called from unknown location
Called from unknown location

Logs saved to `/src/_build/default/test/_build/_tests/TCP tests/Checksum.002.output'.
──────────────────────────────────────────────────────────────────────────────

┌──────────────────────────────────────────────────────────────────────────────┐
│ [FAIL] Checksum 3 data3. │
└──────────────────────────────────────────────────────────────────────────────┘
ASSERT data3
FAIL data3

Expected: 38757' Received: 23295'

Called from unknown location
Called from unknown location

Logs saved to `/src/_build/default/test/_build/_tests/TCP tests/Checksum.003.output'.
──────────────────────────────────────────────────────────────────────────────

┌──────────────────────────────────────────────────────────────────────────────┐
│ [FAIL] Checksum 4 data4. │
└──────────────────────────────────────────────────────────────────────────────┘
ASSERT data4
FAIL data4

Expected: 38752' Received: 23807'

Called from unknown location
Called from unknown location

Logs saved to `/src/_build/default/test/_build/_tests/TCP tests/Checksum.004.output'.
──────────────────────────────────────────────────────────────────────────────

┌──────────────────────────────────────────────────────────────────────────────┐
│ [FAIL] Checksum 5 data5. │
└──────────────────────────────────────────────────────────────────────────────┘
ASSERT data5
FAIL data5

Expected: 37471' Received: 22271'

Called from unknown location
Called from unknown location

Logs saved to `/src/_build/default/test/_build/_tests/TCP tests/Checksum.005.output'.
──────────────────────────────────────────────────────────────────────────────

┌──────────────────────────────────────────────────────────────────────────────┐
│ [FAIL] Checksum 6 real1. │
└──────────────────────────────────────────────────────────────────────────────┘
ASSERT real1
FAIL real1

Expected: 33689' Received: 39675'

Called from unknown location
Called from unknown location

Logs saved to `/src/_build/default/test/_build/_tests/TCP tests/Checksum.006.output'.
──────────────────────────────────────────────────────────────────────────────

┌──────────────────────────────────────────────────────────────────────────────┐
│ [FAIL] Checksum 7 real2. │
└──────────────────────────────────────────────────────────────────────────────┘
ASSERT real2
FAIL real2

Expected: 17139' Received: 7676'

Called from unknown location
Called from unknown location

Logs saved to `/src/_build/default/test/_build/_tests/TCP tests/Checksum.007.output'.
──────────────────────────────────────────────────────────────────────────────

┌──────────────────────────────────────────────────────────────────────────────┐
│ [FAIL] Checksum 8 real3. │
└──────────────────────────────────────────────────────────────────────────────┘
ASSERT real3
FAIL real3

Expected: 17139' Received: 7676'

Called from unknown location
Called from unknown location

Logs saved to `/src/_build/default/test/_build/_tests/TCP tests/Checksum.008.output'.
──────────────────────────────────────────────────────────────────────────────

┌──────────────────────────────────────────────────────────────────────────────┐
│ [FAIL] Checksum 9 real4. │
└──────────────────────────────────────────────────────────────────────────────┘
ASSERT real4
FAIL real4

Expected: 16110' Received: 6651'

Called from unknown location
Called from unknown location

Logs saved to `/src/_build/default/test/_build/_tests/TCP tests/Checksum.009.output'.
──────────────────────────────────────────────────────────────────────────────

┌──────────────────────────────────────────────────────────────────────────────┐
│ [FAIL] Checksum 10 real5. │
└──────────────────────────────────────────────────────────────────────────────┘
ASSERT real5
FAIL real5

Expected: 16623' Received: 7419'

Called from unknown location
Called from unknown location

Logs saved to `/src/_build/default/test/_build/_tests/TCP tests/Checksum.010.output'.