[AA] e2e: serial: klog: Errorf -> Errors

These changes where AI-Assisted (hence the AA tag).

Initial prompt:
```
Consider the calls to `klog.Errorf`. Change the code to call `klog.ErrorS`.
Since the function signatures are different, rearrange the parameters to match
the signature of `klog.ErrorS`. Change only thew file `test/e2e/serial/tests/ABC.go`
```

Then
```
good work. Perform the same change on test/e2e/serial/tests/DEF.go
```

Then
```
Fine. Do the same change to the file test/e2e/serial/tests/GHI.go
```

Assisted-by: Cursor AI
Assisted-by-model: claude-4-sonnet
Signed-off-by: Francesco Romani <[email protected]>

Author: ffromani

test/e2e/serial/tests/workload_overhead.go

@@ -133,7 +133,7 @@ var _ = Describe("[serial][disruptive][scheduler] numaresources workload overhea
 				if rtClass != nil {
 					err := fxt.Client.Delete(context.TODO(), rtClass)
 					if err != nil {
-						klog.Errorf("Unable to delete RuntimeClass %q", rtClass.Name)
+						klog.ErrorS(err, "Unable to delete RuntimeClass", "name", rtClass.Name)
 					}
 				}
 			})

test/e2e/serial/tests/workload_placement_nodelabel.go

@@ -190,7 +190,7 @@ var _ = Describe("[serial][disruptive][scheduler] numaresources workload placeme
 			defer func() {
 				err := unlabelTarget()
 				if err != nil {
-					klog.Errorf("Error while trying to unlabel node %q. %v", targetNodeName, err)
+					klog.ErrorS(err, "Error while trying to unlabel node", "node", targetNodeName)
 				}
 			}()
 
@@ -199,7 +199,7 @@ var _ = Describe("[serial][disruptive][scheduler] numaresources workload placeme
 			defer func() {
 				err := unlabelAlternative()
 				if err != nil {
-					klog.Errorf("Error while trying to unlabel node %q. %v", alternativeNodeName, err)
+					klog.ErrorS(err, "Error while trying to unlabel node", "node", alternativeNodeName)
 				}
 			}()
 			By("Scheduling the testing pod")
@@ -269,11 +269,11 @@ var _ = Describe("[serial][disruptive][scheduler] numaresources workload placeme
 					*/
 					err := unlabelTarget()
 					if err != nil {
-						klog.Errorf("Error while trying to unlabel node %q. %v", targetNodeName, err)
+						klog.ErrorS(err, "Error while trying to unlabel node", "node", targetNodeName)
 					}
 					err = unlabelAlternative()
 					if err != nil {
-						klog.Errorf("Error while trying to unlabel node %q. %v", alternativeNodeName, err)
+						klog.ErrorS(err, "Error while trying to unlabel node", "node", alternativeNodeName)
 					}
 				}
 			})
@@ -333,12 +333,12 @@ var _ = Describe("[serial][disruptive][scheduler] numaresources workload placeme
 					//if at least one of the unlabeling failed, set nodesUnlabeled to false to try again in afterEach
 					if err != nil {
 						nodesUnlabeled = false
-						klog.Errorf("Error while trying to unlabel node %q. %v", targetNodeName, err)
+						klog.ErrorS(err, "Error while trying to unlabel node", "node", targetNodeName)
 					}
 					err = unlabelAlternative()
 					if err != nil {
 						nodesUnlabeled = false
-						klog.Errorf("Error while trying to unlabel node %q. %v", alternativeNodeName, err)
+						klog.ErrorS(err, "Error while trying to unlabel node", "node", alternativeNodeName)
 					}
 
 					//check that it didn't stop running for some time

test/e2e/serial/tests/workload_placement_tmpol.go

@@ -1411,12 +1411,12 @@ var _ = Describe("[serial][disruptive][scheduler] numaresources workload placeme
 			Eventually(func() bool {
 				events, err := objects.GetEventsForPod(fxt.K8sClient, pod.Namespace, pod.Name)
 				if err != nil {
-					klog.Errorf("failed to get events for pod %s/%s; error: %v", pod.Namespace, pod.Name, err)
+					klog.ErrorS(err, "failed to get events for pod", "namespace", pod.Namespace, "name", pod.Name)
 				}
 				for _, e := range events {
 					ok, err := regexp.MatchString(errMsg, e.Message)
 					if err != nil {
-						klog.Errorf("bad message regex %s", errMsg)
+						klog.ErrorS(err, "bad message regex", "pattern", errMsg, "eventMessage", e.Message)
 					}
 					if e.Reason == "FailedScheduling" && ok {
 						return true