RFR: 8256008: UL does not report anything if disk writing fails [v2]

[Yasumasa Suenaga]

> If there are no disk space enough to write UL, it does not report. So the user cannot know lack of logs timely.
> 
> `LogFileStreamOutput::write()` uses `jio_fprintf()` and `fflush()` to write log. However return values from them would not be checked.
> We should check them, and should report what happened if error occurred.
> 
> 
> How to reproduce on Linux:
> 
> 1. Mount tmpfs with 512K
> 
> $ mkdir /tmp/tmp
> $ mount -t tmpfs -o size=512k tmpfs /tmp/tmp
> 
> 2. Run `java` with `-Xlog`
> 
> $ java -Xlog:all=trace:file=/tmp/tmp/all.log --version

Yasumasa Suenaga has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains four commits:

 - refactoring
 - Merge branch 'master' into JDK-8256008
 - Fix typo
 - 8256008: UL does not report anything if disk writing fails

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

Changes: https://git.openjdk.java.net/jdk/pull/1106/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1106&range=01
  Stats: 55 lines in 3 files changed: 37 ins; 2 del; 16 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1106.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1106/head:pull/1106

PR: https://git.openjdk.java.net/jdk/pull/1106