test_tiles2gpkg.py: test_matrix_width (470) and test_matrix_height (486) are failing

[GitHubRGI]

Tile matrix size calculations were updated to reflect a full theoretical tile matrix. In previous versions, tiles2gpkg_parallel.py would calculate tile matrix height and width values based on what tiles actually reside in the raster tile table. Now, the calculation takes any theoretical, fully transparent tiles that should exist in the raster table but do not.

This failure of transparent tiles to exist in the raster tile table can be blamed on gdal2tiles not always making them.

Correct these two test cases to compare the matrix height and width values for what they should actually be.

[JACochran]

The commit 92af72e corrects the two test cases as well as an additional rounding error in a third test.