time differences to span the full range of dates supported by SQLite. Also fix some inaccuracies in the computation of time differences and add new test cases. FossilOrigin-Name: d57ddbf4eeeb3ccfe31871f098045b9e58634153a3c3030f597cb58c1177218a
FossilOrigin-Name: f14633ce6ddf28a14b03e2da623d96e439966aa3fc30c26cb0be59c0e15b3e9c
FossilOrigin-Name: cff293b0a79107def7bfe54fd60ac4a721c5098c85229d9b46a4e2c4cbf34a6a
cases are passing. FossilOrigin-Name: 2cf6518140d61e2123dc20f39d7e97e7bce17e7641405df7fd63e1cdda444ae0