Fix walltime computation bug

Because we logged finished step events before the current batch
of events were processed, there were situations where the snapshot from a previous
failed realization was out of date.

This solves that problem. There is still a residual problem that will surface if
walltime is to be computed for all steps: If a failure event for a step and its
success event from the subsequent run is in the same batch of events, we can get
a negative walltime computed. This problem is ignored as the walltime computation
is only interesting (currently) for walltimes > 120 seconds, where this cannot
happen (max time between batches is 2 seconds).

src/ert/ensemble_evaluator/_ensemble.py

@@ -180,6 +180,14 @@ def _log_completed_fm_step(
 
     def update_snapshot(self, events: Sequence[Event]) -> EnsembleSnapshot:
         snapshot_mutate_event = EnsembleSnapshot()
+        for event in events:
+            snapshot_mutate_event = snapshot_mutate_event.update_from_event(
+                event, source_snapshot=self.snapshot
+            )
+        self.snapshot.merge_snapshot(snapshot_mutate_event)
+        if self.snapshot.status is not None and self.status != self.snapshot.status:
+            self.status = self._status_tracker.update_state(self.snapshot.status)
+
         for event in events:
             if isinstance(event, (ForwardModelStepSuccess, ForwardModelStepFailure)):
                 step = (
@@ -188,12 +196,7 @@ def update_snapshot(self, events: Sequence[Event]) -> EnsembleSnapshot:
                     .get(event.fm_step)
                 )
                 self._log_completed_fm_step(event, step)
-            snapshot_mutate_event = snapshot_mutate_event.update_from_event(
-                event, source_snapshot=self.snapshot
-            )
-        self.snapshot.merge_snapshot(snapshot_mutate_event)
-        if self.snapshot.status is not None and self.status != self.snapshot.status:
-            self.status = self._status_tracker.update_state(self.snapshot.status)
+
         return snapshot_mutate_event
 
     async def send_event(