Add parse test for chained assignment.
Make tests run for both current and future parser.

Tests were hardwired to run for only future/eparser. Now all tests
where parser is involved runs for both current/classic and
future/eparser (except when testing methods; where parsing is only
done in order to construct a call; it is the function that is tested,
not the parsing). The collect method testing includes testing the
various ways a call can be made to it, but this is the only place; this
because it is more work to unwire all the others when the final style
for lambdas gets picked.
Remove unused copy of type_creator.rb
Add setting -parser [current/future] that selects which parser to use.

This also makes the ParserFactory select parser based on this setting.
Make vardef produce rvalue.

This ensures that chained assignments work as expected (if they are
allowed by the validator).