For a given absolute or relative path, measure the size of the file.
This is useful for measuring if the cache has increased as expected
after moving a camera or decreased after cleaning up.
In a more hackish manner, could be used for collecting binary size
statistics of shared libraries.
Before this change, the found paths to the expected images
erroneously included the path to the `metrics.json` file
(if this file was present) leading to raising of an
unhandled exception.
This change adds filter command line option to render test runner,
so that test can be filtered by providing regular expression, for instance:
mbgl-render-test -f .*hillshade.*
The `mapbox-gl-native`-specific render tests expected results will
be stored at the `render-test/expected/` subfolder.
Test runner will automatically put new expected results there if
invoked with `UPDATE=true`.
Two render tests failing only with mbgl-render-tests are added to platform
specific ignores. This is to be extended with fill-extrusion-pattern failing only on mac.
