- they are mostly pointless in all major jurisdictions
- many big corporations and projects already don't use them
- saves us from pointless churn
- git keeps history for us
- the year range is kept in COPYING
checksrc is updated to allow non-year using copyright statements
Closes#10205
Reproduces #9735 and verifies the subsequent fix. The original issue
uses a pipe that cannot be rewound, but this test case instead sets a
callback without rewind ability to get roughly the same properties but
being a much more portable test.