roachtest: fix overlapping failure injection bug

This change fixes a bug regarding failure injections overlapping over
each other when not intended. Marks the mutator step itself to also set
unavailableNodes so sequential failure injections don't insert into
them.

Epic: none

Release note: none

Fixes: #151522

Author: Dev-Kyle

pkg/cmd/roachtest/roachtestutil/mixedversion/mutators.go

@@ -488,6 +488,8 @@ func (m panicNodeMutator) Generate(
 			return s == restartStep[0]
 		})
 		failureContextSteps.MarkNodesUnavailable(true, false)
+		addPanicStep[0].hasUnavailableSystemNodes = true
+		addRestartStep[0].hasUnavailableSystemNodes = true
 
 		mutations = append(mutations, addPanicStep...)
 		mutations = append(mutations, addRestartStep...)
@@ -623,6 +625,10 @@ func (m networkPartitionMutator) Generate(
 		})
 
 		failureContextSteps.MarkNodesUnavailable(true, true)
+		addPartition[0].hasUnavailableSystemNodes = true
+		addPartition[0].hasUnavailableTenantNodes = true
+		addRecoveryStep[0].hasUnavailableSystemNodes = true
+		addRecoveryStep[0].hasUnavailableTenantNodes = true
 
 		mutations = append(mutations, addPartition...)
 		mutations = append(mutations, addRecoveryStep...)

pkg/cmd/roachtest/roachtestutil/mixedversion/planner.go

@@ -151,6 +151,12 @@ type (
 		reference *singleStep
 		impl      singleStepProtocol
 		op        mutationOp
+		// unavailableNodes are marked for each step during the `Generate`
+		// method, but the mutator steps themselves are not created until
+		// `applyMutations` is called. These booleans denote whether
+		// the mutator sets any nodes to unavailable.
+		hasUnavailableSystemNodes bool
+		hasUnavailableTenantNodes bool
 	}
 
 	// stepSelector provides a high level API for mutator
@@ -1537,6 +1543,10 @@ func (plan *TestPlan) applyMutations(rng *rand.Rand, mutations []mutation) {
 					impl:    mut.impl,
 					rng:     rngFromRNG(rng),
 				}
+				newSingleStep.context.System.hasUnavailableNodes = mut.hasUnavailableSystemNodes
+				if newSingleStep.context.Tenant != nil {
+					newSingleStep.context.Tenant.hasUnavailableNodes = mut.hasUnavailableTenantNodes
+				}
 			}
 
 			switch mut.op {