[11u] RFR: JDK-8227080 backport: (fs) Files.newInputStream(...).skip(n) is slow

[Ilarion Nakonechnyy]

Dear Sirs, I’d like to backport JDK-8227080 to JDK11.

The patch applied unclear, a small correction in comment was done. Build successfully and run tier-1 on mac x86_64.
Could you please review the changes?
webrev: http://cr.openjdk.java.net/~yan/8227080_wr/webrev.00/
Bug:  https://bugs.openjdk.java.net/browse/JDK-8227080

Thanks.