Saxon XSLT and XQuery Processor

In XPath 2.0, an expression such as

./( $a, $b)

or

($a, $b)/.

is supposed to deliver its results in document order.
It doesn't: Saxon ignores the "./" or "/.", which is
legitimate in XPath 1.0 but not in XPath 2.0

Applies to Saxon 7.x releases up to and including 7.2;
not relevant to 6.5.x.

Source code fixed, test case bug92 added. Found during
code inspection.