Ruby: put AST node locations in a single table

[nickrolfe]

This should make getLocation() on generated nodes faster.

I generated the upgrade/downgrade scripts with some quick hacks to the generator program, and only hand-edited the results for formatting. That means reviewers should feel confident that, for the upgrades/downgrades, they only need to check:

• {ruby,erb}_ast_node_parent <-> {ruby,erb}_ast_node_info upgrades/downgrades.
• {ruby,erb}_tokeninfo modifications
• and just a small sample of the *_def table modifications.

I tested them by:

1. Running all the qltests with --search-path=main-extractor-pack:ql so that they would use an extractor from main and upgrade the dbs on the fly.
2. Building a large Ruby database with an extractor from main, upgrading it, then downgrading it, and checking that all the relations in the original and downgraded databases were byte-for-byte identical.

[aibaars]

LGTM

[nickrolfe]

Let's at least wait for DCA to finish before merging.

[nickrolfe]

The DCA results look good, and show a nice speedup on analysis time.