`ParseByteUnits()` is the only parsing function in `strencodings.cpp`
lacking a fuzz test. Add a test case to check the function against
arbitrary strings and randomized default_multiplier's.
The 'FEE' parameter in test/functional/feature_dbcrash.py::
generate_small_transaction() is not a fee rate, but an
absolute fee. Hence, it doesn't make sense to replace it
with node relay based fee calculation. Get rid of the TODO
comment suggesting otherwise.
In test/functional/interface_usdt_net.py, assert_equal is already
used to check for equality between objects. Replace 'assert.*=='
with 'assert_equal' and 'assert.*>' with 'assert_greater_than'
to further easify debugging.