[query] Do not attempt to remove vector references if there is no hail context (#11067)
[query] Do not attempt to remove vector references if there is no hail context (#11067)

This can occur if stop is called before a garbage collection
hail-is/hail,hail-is/hail,hail-is/hail,hail-is/hail,hail-is/hail,hail-is/hail,hail-is/hail,hail-is/hail