Revert "Uber-dirty hack to make the PPI and non-PPI parsers usable in one run"

This reverts commit 55a9b65ec3ed1c56e88ee8ddfc83586c97d88c26.

(I'll look at a more general solution to this, after refactoring
::Naive.)

Conflicts:

	bin/perl-tags
	lib/Perl/Tags.pm
Refactor get_parsers into ::Naive