Update TESTING.asciidoc for new :qa:os test style (#48023)
Update TESTING.asciidoc for new :qa:os test style (#48023)

* Update testing document for new packaging tests

The TESTING.asciidoc document had gotten out of date due to some new and
wonderful changes in our vagrant testing code. I've removed all of the
instructions that no longer work, and added working examples and descriptions
in their place.

GlenRSmith/elasticsearch,robin13/elasticsearch,gingerwizard/elasticsearch,robin13/elasticsearch,uschindler/elasticsearch,gingerwizard/elasticsearch,robin13/elasticsearch,GlenRSmith/elasticsearch,scorpionvicky/elasticsearch,GlenRSmith/elasticsearch,uschindler/elasticsearch,uschindler/elasticsearch,GlenRSmith/elasticsearch,gingerwizard/elasticsearch,HonzaKral/elasticsearch,HonzaKral/elasticsearch,scorpionvicky/elasticsearch,robin13/elasticsearch,gingerwizard/elasticsearch,scorpionvicky/elasticsearch,scorpionvicky/elasticsearch,nknize/elasticsearch,scorpionvicky/elasticsearch,gingerwizard/elasticsearch,HonzaKral/elasticsearch,GlenRSmith/elasticsearch,uschindler/elasticsearch,robin13/elasticsearch,nknize/elasticsearch,nknize/elasticsearch,uschindler/elasticsearch,HonzaKral/elasticsearch,gingerwizard/elasticsearch,gingerwizard/elasticsearch,nknize/elasticsearch,nknize/elasticsearch