Change to Test Suite

[Preston Carman <pr...@apache.org>]

I discovered that XQTS has tests that could have multiple possible
query responses. A system that supports static type checking could
execute a query and throw an error. In contrast, a system without
static type checking would produce a result. XQTS has been written to
allow for both possibilities. The following example query demonstrates
how a static type error could be fixed during runtime and produce an
result.

remove( (1, "two"), 2) eq 1

Static type checking throws an error while without static type
checking it produces a result. I changed our testing suite to consider
this case. Before if the test suite suggested only the error was
correct for the query, it would not even check if a result was
possible.

Please review my change [1].

[1] https://github.com/apache/vxquery/pull/112