PreviousOrigin is not updated in PcesFileReader, short-circuiting one of the file validity checks

PcesFileReader compares previousOrigin in `buildFileHandler` to the one in the file to ensure proper ordering, but it never updates the local variable, so it always compares it against -1.

It should be corrected, after checking if that invariant really holds and a test case should be created to make sure it catches origin failure

Start in PcesFileReader.buildFileHandler and verify whether the previousOrigin ordering invariant holds across files. Add a regression test that exercises an invalid origin and confirms the validity check catches it; done means the local previousOrigin state is maintained and the test fails for the invalid ordering.

Written by the indexing model from the issue text.