Issues with OData query generation logic

When the ODataExpressionToSQLBuilder changes the ctxExpression, ctxQuery and other state it needs to revert back, but currently does not.

For example reordering the predicate:

/odata4/vdb/PM1/G1?$filter=e1 eq $root/G1(1)/e1

to

/odata4/vdb/PM1/G1?$filter=$root/G1(1)/e1 eq e1

results in a source query:

SELECT g0.e1, g0.e2, g0.e3 FROM PM1.G1 AS g0 WHERE (SELECT g1.e1 FROM PM1.G1 AS g1 WHERE g1.e2 = 1) = (SELECT g1.e1 FROM PM1.G1 AS g1 WHERE g1.e2 = 1) ORDER BY g0.e2

That has both sides of the predicate as subqueries.