Particularly, the final output order of a table/set is sensitive to
order of input/insertions and some tests were converting
std::unordered_{set,map} to Zeek table/set and iteration over those
standard containers may not always loop through elements in the same
order across all platforms.
Haven't checked different build configurations yet, but all except
a few SumStats tests are stable for me now. The external tests
are also completely failing, but haven't looked at those yet.
This also updates all usages of the deprecated Val ctor to use
either IntervalVal, TimeVal, or DoubleVal ctors. The reason for
doing away with the old constructor is that using it with TYPE_INTERVAL
isn't strictly correct since there exists a more specific subclass,
IntervalVal, with overriden ValDescribe() method that ought to be used
to print such values in a more descriptive way.
