RFR: 8272297: FileInputStream should override transferTo() for better performance [v2]

[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: Set source position after FC.transferTo(); add test

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5097/files
  - new: https://git.openjdk.java.net/jdk/pull/5097/files/54f14550..a199fc67

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5097&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5097&range=00-01

  Stats: 133 lines in 2 files changed: 132 ins; 0 del; 1 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