RFR: 6478546: FileInputStream.read() throws OutOfMemoryError when there is plenty available [v2]

[Brian Burkhalter]

> Limit native memory allocation and move write loop from the native layer into Java. This change should make the OOME reported in the issue much less likely.

Brian Burkhalter has updated the pull request incrementally with three additional commits since the last revision:

 - 6478546: Decrease malloc limit to 1.5 MB
 - 6478546: Minor refactoring
 - 6478546: Prevent short read

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/14981/files
  - new: https://git.openjdk.org/jdk/pull/14981/files/8d7b3478..69941de4

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14981&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14981&range=00-01

  Stats: 99 lines in 6 files changed: 57 ins; 28 del; 14 mod
  Patch: https://git.openjdk.org/jdk/pull/14981.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14981/head:pull/14981

PR: https://git.openjdk.org/jdk/pull/14981