RFR: 6478546: FileInputStream.read() throws OutOfMemoryError when there is plenty available [v6]

[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.

Brian Burkhalter has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains ten additional commits since the last revision:

 - 6478546: Use dynamically sized temporary direct buffers
 - Merge
 - Merge
 - 6478546: Add break in write loop on ExceptionOccurred
 - Merge
 - 6478546: Clean up io_util.c
 - Merge
 - 6478546: Decrease malloc'ed buffer maximum size to 64 kB
 - 6478546: FileInputStream.read() throws OutOfMemoryError when there is plenty available

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/8235/files
  - new: https://git.openjdk.org/jdk/pull/8235/files/00521485..e6f3b457

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=8235&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=8235&range=04-05

  Stats: 39139 lines in 1021 files changed: 15199 ins; 12013 del; 11927 mod
  Patch: https://git.openjdk.org/jdk/pull/8235.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/8235/head:pull/8235

PR: https://git.openjdk.org/jdk/pull/8235