Lock SipHash-2-4 behavior into shared vectors before refactoring its round and finalization code.
Store inputs as ordered hex byte blocks so `CSipHasher` and the independent Python implementation hash the same byte sequence, with applicable `PresaltedSipHasher` overloads checked against the same vectors.
Add the 64 official SipHash-2-4 vectors alongside block-partition and empty-block cases for the generic path.
Move randomized generic/fixed comparisons to the integer fuzzer.
SipHash-1-3-UJ coverage can add expected outputs for compatible 8- and 32-byte block sequences.
The Python test reads a build-tree copy so functional-test staging behaves consistently when files are symlinked or copied.
Co-authored-by: Pieter Wuille <pieter@wuille.net>
Reorganize functional test framework unit tests to run in parallel
with other functional tests.
The option `skipunit` is removed, since unit tests no longer delay
functional test execution.
Unit tests are run by default when running all tests, and can be
run explicitly with `feature_framework_unit_tests.py` when running
a subset of tests.
