Add support to create ValueArrays with the global value function

[skwlilac]

Within JEXL it is useful possible to create both collections (HashMaps and HashSets) and array which are useful when micro-parsing table cell values that contain some form of repetitive structure. It is desirable to pass back an array of the resulting values as a ValueArray to a template as a means passing a multi-valued result.

  var res = { 'one':'one' }                     // Create a Map
  res.clear() ;                                       // Empty the Map
  ....                                                     // Work to fill the map - assume that map keys are ValueNodes representing RDF nodes.
  return value(res.keySet()) 

PR proposing a fix to follow.

[skwlilac]

Addressed by 1e6cfa2