Return a set of non-conditional runs of 《op》 nodes with the given names.
For example, 《… h q; cx q,q; cx q,q; h q; ..》 would produce the tuple of cx nodes as an element of the set returned from a call to collect_runs([《cx》]). If instead the cx nodes were 《cx q,q; cx q,q;》, the method would still return the pair in a tuple. The namelist can contain names that are not in the circuit’s basis.
Nodes must have only one successor to continue the run.