Suggestion: re-structure the wiki instructions to install and configure jtreg

[Julius Gamanyi]

Hi,

The suggestion I have in mind is to change the structure of the
instructions to install and configure jtreg; the instruction in this useful
guide "Adopt OpenJDK Intermediate & Advance experience," (
https://docs.google.com/document/d/17cgYBD_rIkj9xdqTR0CJfb_cBJe8radM2iaPZG3W4y0/edit?pli=1#)
and the InstallJtreg wiki page (
https://java.net/projects/adoptopenjdk/pages/InstallJtreg).

I was getting somewhat lost, other times needing to work out why some
dependencies are installed via apt-get whereas others are downloaded and
installed in the /opt directory.

That way, after someone follows the steps, they would be able to:
  * know the relationship between the guide, the installJtreg wiki page (
https://java.net/projects/adoptopenjdk/pages/InstallJtreg), the
top-level-steps-of-jtreg (http://openjdk.java.net/jtreg/), the
top-level-steps-of-building-jtreg (http://openjdk.java.net/jtreg/build.html),
and the Eclipse Project for JTReg wiki page (
https://java.net/projects/adoptopenjdk/pages/EclipseProjectForJTReg);

  * know the trade-offs between using a pre-built artifact and building
from the latest Mercurial repositories;

  * have a consistent way of installing dependencies, and working out where
to find the dependencies that have been installed - E.g., you need the path
to set some variables in jtreg/make/build.properties; you also need to
ensure that the ant version that Eclipse is using is the same one used when
running on CLI;

  * some steps in the wiki page for setting up Eclipse are needed whether
or not you're going to be using Eclipse; they also match the
top-level-steps-of-building-jtreg (http://openjdk.java.net/jtreg/build.html)
but do not explicitly refer to that site.

Perhaps I can help with this.

Thanks,
Julius