RFR: 8272297: FileInputStream should override transferTo() for better performance [v3]

[Brian Burkhalter]

> Please consider this request to add an override `java.io.FileInputStream.transferTo(OutputStream)` with improved performance if the parameter is a `FileOutputStream`.

Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:

  8272297: Improve growing source and partial transfer cases

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5097/files
  - new: https://git.openjdk.java.net/jdk/pull/5097/files/a199fc67..796248e7

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5097&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5097&range=01-02

  Stats: 13 lines in 1 file changed: 1 ins; 3 del; 9 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5097.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5097/head:pull/5097

PR: https://git.openjdk.java.net/jdk/pull/5097