[jdk7u] RFR: 8285523: Improve test java/io/FileOutputStream/OpenNUL.java [v3]

[Olga Mikhaltsova]

> I'd like to backport JDK-8285523 to jdk7u.
> 
> The patch applied not cleanly due to the directory structure differences:
> `test/jdk/java/io/FileOutputStream/OpenNUL.java`-> `jdk/test/java/io/FileOutputStream/OpenNUL.java`
> 
> Tested manually as follow:
> $JTREG_HOME/bin/jtreg -jdk:$BUILD_HOME /cygdrive/c/projects/jdk7u-fork/jdk/test/java/io/
> No regression in the above tests' group.

Olga Mikhaltsova 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 three additional commits since the last revision:

 - Merge master
 - Backport f42631e354d4abf7994abd92aa5def6b2ceeab3a
 - Backport 03cbb48e6a1d806f204a39bbdbb4bc9be9e57a41

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

Changes:
  - all: https://git.openjdk.org/jdk7u/pull/10/files
  - new: https://git.openjdk.org/jdk7u/pull/10/files/412cd71d..80b28426

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk7u&pr=10&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk7u&pr=10&range=01-02

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk7u/pull/10.diff
  Fetch: git fetch https://git.openjdk.org/jdk7u pull/10/head:pull/10

PR: https://git.openjdk.org/jdk7u/pull/10