[JENKINS-19473] Removing workaround since root bug should be fixed in jzlib 1.1.3.
FilePath#testErrorMessageInRemoteCopyRecursive was exceptionally slow to run as it was building 10000 test files. The same error can be demonstrated with 1 file.
Migrated some usages of GNUCLibrary to the jnr PosixAPI, fixed 'mvn -Plight-test install' on ubuntu with OpenJDK.