Remove sometimes falsely thrown exception + reset root node fully

Author: MaartenS11

src/main/kotlin/be/ugent/topl/mio/debugger/Debugger.kt

@@ -66,9 +66,6 @@ open class Debugger(private val connection: Connection, start: Boolean = true, p
                     //println(checkpoint)
 
                     if (checkpoint.instructions_executed == 0 && checkpoints.size > 0) {
-                        if (checkpoint.snapshot.pc != checkpoints.last()!!.snapshot.pc) {
-                            throw RuntimeException("Received a checkpoint with a different pc but with 0 executed instructions since the last checkpoint!")
-                        }
                         System.err.println("WARNING: Received a checkpoint that we already have!")
                         continue
                     }

src/main/kotlin/be/ugent/topl/mio/ui/InteractiveDebugger.kt

@@ -375,7 +375,7 @@ class InteractiveDebugger(
         debugger.startReading()
         debugger.setSnapshotPolicy(Debugger.SnapshotPolicy.Tracing(listOf(ExecutionState.ProgramCounter)))
         debugger.reset()
-        debugger.graph.currentNode.removeAllChildren()
+        debugger.graph.currentNode = MultiverseNode()
         pause()
     }