Removing some variables from parser_t that are no longer used in the new
execution model
Fix line number reporting in new parser
Fix for issue where pager contents may stay around if you executed a
command with pager contents visible
Rewrite parser_t::current_line() to respect new parser
Rewrite parser_t::eval_args to use new AST parser
Correct the last keyword enum to reflect the actual last keyword
Add some tests for parse_util_detect_errors_in_argument
Rewrite parser_t::test_args and parser_t::eval_args to use new parser
Remove additional dead code from old parser
Remove current_tokenizer and current_tokenizer_pos from old parser