artifact_extractor does not accept absolute path

[lolski]

The artifact_extractor will fail to extract artifacts when the output path is specified as absolute path like below. Moreover, the failure is silent (ie., without throwing any error):

bazel run //test:typedb-extractor-linux /home/grabl/$GRABL_REPO/dist/typedb-all-linux/

If a relative path is supplied instead, the rule will work successfully:

bazel run //test:typedb-extractor-linux dist/typedb-all-linux/

This isn't ideal and the rule should be made to work for any valid file paths, both absolute and relative.