Add split e2e test with memory checking [v3]

[gunnsth]

The split test reads and writes back out a single page from each test file.
Tests the efficiency of working with parts of large files.
Checks the hash of the output to avoid regressions.
Measures duration and memory allocations.

[codecov]

Codecov Report

Merging #410 into v3 will decrease coverage by 5.32%.
The diff coverage is 86.2%.

@@            Coverage Diff             @@
##               v3     #410      +/-   ##
==========================================
- Coverage   60.96%   55.63%   -5.33%     
==========================================
  Files         151      153       +2     
  Lines       27502    27531      +29     
==========================================
- Hits        16767    15318    -1449     
- Misses      10319    10345      +26     
- Partials      416     1868    +1452

Impacted Files	Coverage Δ
pdf/internal/e2etest/memory_measure.go	100% <100%> (ø)
pdf/internal/e2etest/utils.go	60% <60%> (ø)
pdf/core/security/handlers.go	33.33% <0%> (-16.67%)	⬇️
pdf/model/optimize/image_ppi.go	59.7% <0%> (-16.42%)	⬇️
pdf/model/reader.go	48.34% <0%> (-15.17%)	⬇️
pdf/ps/exec.go	62.96% <0%> (-14.82%)	⬇️
pdf/ps/operations.go	53.45% <0%> (-13.84%)	⬇️
pdf/model/signature_handler.go	55.04% <0%> (-13.77%)	⬇️
pdf/core/stream.go	31.08% <0%> (-13.52%)	⬇️
pdf/extractor/image.go	66.08% <0%> (-13.05%)	⬇️
... and 97 more

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