Python: Fix tests

With `ModuleVariableNode`s now appearing for _all_ global variables (not
just the ones that actually seem to be used), some of the tests changed
a bit. Mostly this was in the form of new flow (because of new nodes
that popped into existence). For some inline expectation tests, I opted
to instead exclude these results, as there was no suitable location to
annotate. For the normal tests, I just accepted the output (after having
vetted it carefully, of course).

python/ql/lib/utils/test/dataflow/MaximalFlowTest.qll

@@ -8,7 +8,9 @@ module MaximalFlowTest implements FlowTestSig {
 
   predicate relevantFlow(DataFlow::Node source, DataFlow::Node sink) {
     source != sink and
-    MaximalFlows::flow(source, sink)
+    MaximalFlows::flow(source, sink) and
+    // exclude ModuleVariableNodes (which have location 0:0:0:0)
+    not sink instanceof DataFlow::ModuleVariableNode
   }
 }