roachtest: fix mixed cluster and node versions for tenant span stats

This change ensures we don't make assertions when the cluster is in a
finalizing state (i.e. waiting for cluster version to upgrade). We
cannot make any meaningful assertions in this state without introducing
flakiness into the test, as such we skip this state. Additionally, this
allows us to simplify the test logic.

Release note: None

pkg/cmd/roachtest/tests/mixed_version_tenant_span_stats.go

@@ -88,6 +88,11 @@ func registerTenantSpanStatsMixedVersion(r registry.Registry) {
 				mixedVersionReqError := "unable to service a mixed version request"
 				unknownFieldError := "unknown field"
 
+				// Skip finalizing state.
+				if h.Context().Finalizing {
+					return nil
+				}
+
 				// If we have nodes in mixed versions.
 				if len(h.Context().FromVersionNodes) > 0 && len(h.Context().ToVersionNodes) > 0 {
 					prevVersNodeID := h.Context().FromVersionNodes[0]
@@ -148,37 +153,6 @@ func registerTenantSpanStatsMixedVersion(r registry.Registry) {
 					if !expectedCurrToPrev && !expectedUnknown {
 						return errors.Newf("expected '%s' or '%s' in error message, got: '%v'", mixedVersionReqError, expectedUnknown, errOutput.Error)
 					}
-				} else {
-					// All nodes are on one version, but we're in mixed state (i.e. cluster version is on a different version)
-					var issueNodeID int
-					var dialNodeID int
-					// All nodes on current version
-					if len(h.Context().ToVersionNodes) == 4 {
-						issueNodeID = h.Context().ToVersionNodes[0]
-						dialNodeID = h.Context().ToVersionNodes[1]
-					} else {
-						// All nodes on previous version
-						issueNodeID = h.Context().FromVersionNodes[0]
-						dialNodeID = h.Context().FromVersionNodes[1]
-					}
-					// Dial a node for span stats.
-					l.Printf("Dial a node for span stats (different cluster version).")
-					res, err = fetchSpanStatsFromNode(ctx, l, c, c.Node(issueNodeID), newReqBody(dialNodeID, startKey, endKey))
-					if err != nil {
-						return err
-					}
-					// Expect an error in the stdout - mixed version error.
-					// Ensure the result can be marshalled into a valid error response.
-					err = json.Unmarshal([]byte(res.Stdout), &errOutput)
-					if err != nil {
-						return err
-					}
-					// Ensure we get the expected error.
-					mixedClusterVersionErr := assertExpectedError(errOutput.Message, mixedVersionReqError)
-					expectedUnknown := assertExpectedError(errOutput.Message, unknownFieldError)
-					if !mixedClusterVersionErr && !expectedUnknown {
-						return errors.Newf("expected '%s' or '%s' in error message, got: '%v'", mixedVersionReqError, unknownFieldError, errOutput.Error)
-					}
 				}
 				return nil
 			})