RFR: 8284638: store skip buffers in InputStream Object

[XenoAmess]

@jmehrens what about this then?
I think it safe now(actually this mechanism is learned from Reader)

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Commit messages:
 - store skip buffers in InputStream Object

Changes: https://git.openjdk.java.net/jdk/pull/5872/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5872&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8284638
  Stats: 9 lines in 1 file changed: 8 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5872.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5872/head:pull/5872

PR: https://git.openjdk.java.net/jdk/pull/5872