RFR: 6478546: FileInputStream.read() throws OutOfMemoryError when there is plenty available

[Brian Burkhalter]

Modify native multi-byte read-write code used by the `java.io` classes to limit the size of the allocated native buffer thereby decreasing off-heap memory footprint and increasing throughput.

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Commit messages:
 - 6478546: FileInputStream.read() throws OutOfMemoryError when there is plenty available

Changes: https://git.openjdk.java.net/jdk/pull/8235/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8235&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-6478546
  Stats: 93 lines in 2 files changed: 52 ins; 8 del; 33 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8235.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8235/head:pull/8235

PR: https://git.openjdk.java.net/jdk/pull/8235