RFR: 8285915: failure_handler: gather the contents of /etc/hosts file [v2]

[Jaikiran Pai]

> Can I please get a review of this change which addresses https://bugs.openjdk.java.net/browse/JDK-8285915?
> 
> With this change, the environment details collected by the failure handler will now include the contents of the `/etc/hosts/` file, which can be useful in certain cases when debugging network tests that fail.
> 
> Testing done (on macOS):
> 
> 
> cd test/failure_handler 
> make test
> 
> Then verified that the generated environment.html had the `/etc/hosts` file content

Jaikiran Pai has updated the pull request incrementally with one additional commit since the last revision:

  print contents of hosts file in windows failure handler

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/8466/files
  - new: https://git.openjdk.java.net/jdk/pull/8466/files/673fd0bd..8591d0c0

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=8466&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=8466&range=00-01

  Stats: 5 lines in 1 file changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8466.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8466/head:pull/8466

PR: https://git.openjdk.java.net/jdk/pull/8466