Add newly released jnr-posix to fix #1115.
Use builtin posix vs creating one per regularfileresource.  Besides overhead of lots of new jnr-posix instances we need to push this into resource because we do not know if native is enabled or disabled.  On platforms with native unable to load lstat could not execute.
Change FileResource.stat() to not rely on passed in posix since RegularFileResource now has a bonafide posix instance.  Note: this breaks a public API but it has only existed for one point release so I am willing to take the heat...
Change FileResource.lstat() to not rely on passed in posix since RegularFileResource now has a bonafide posix instance.  Note: this breaks a public API but it has only existed for one point release so I am willing to take the heat...
Change FileResource.openDescriptor() to not rely on passed in posix since RegularFileResource now has a bonafide posix instance.  Note: this breaks a public API but it has only existed for one point release so I am willing to take the heat...