Revert "local state: clone check to avoid side effect"

This reverts commit af1243c725.

agent/local/state.go

@@ -335,9 +335,6 @@ func (l *State) AddCheck(check *structs.HealthCheck, token string) error {
 		return fmt.Errorf("no check")
 	}
 
-	// clone the check since we will be modifying it.
-	check = check.Clone()
-
 	if l.discardCheckOutput.Load().(bool) {
 		check.Output = ""
 	}