Don't quit debugger when the program terminates, only after `quit`.

pkg/dartino_compiler/lib/cli_debugger.dart

Index: pkg/dartino_compiler/lib/cli_debugger.dart
diff --git a/pkg/dartino_compiler/lib/cli_debugger.dart b/pkg/dartino_compiler/lib/cli_debugger.dart
index d8340662e69956b1e925a2f43090020a814e5c72..3be29bc1dbd46c533bb8254bcd414eda59fdc4ec 100644
--- a/pkg/dartino_compiler/lib/cli_debugger.dart
+++ b/pkg/dartino_compiler/lib/cli_debugger.dart
@@ -77,6 +77,7 @@ class CommandLineDebugger {
   bool verbose = true;
 
   String previousLine = '';
+  bool quitDebugger = false;
 
   int processPagingCount = 10;
   int processPagingCurrent = 0;
@@ -386,6 +387,7 @@ class CommandLineDebugger {
       case 'q':
       case 'quit':
         await vmContext.terminate();
+        quitDebugger = true;
         break;
       case 'r':
       case 'run':
@@ -444,7 +446,6 @@ class CommandLineDebugger {
         break;
     }
     previousLine = line;
-    if (!vmContext.terminated) printPrompt();
   }
 
   bool toggleVerbose() => verbose = !verbose;
@@ -498,9 +499,14 @@ class CommandLineDebugger {
   Future<int> run(SessionState state, {Uri snapshotLocation}) async {
     await vmContext.initialize(state, snapshotLocation: snapshotLocation);
     writeStdoutLine(BANNER);
-    printPrompt();
     StreamIterator streamIterator = new StreamIterator(stream);
-    while (await streamIterator.moveNext()) {
+
+    Future<bool> getNext() async {
+      printPrompt();
+      return await streamIterator.moveNext();
+    }
+
+    while (!quitDebugger && await getNext()) {
       try {
         await handleLine(streamIterator);
       } catch (e, s) {
@@ -511,11 +517,10 @@ class CommandLineDebugger {
         await cancel;
         return new Future.error(e, s);
       }
-      if (vmContext.terminated) {
-        await streamIterator.cancel();
-      }
     }
-    if (!vmContext.terminated) await vmContext.terminate();
+    if (!vmContext.terminated) {
+      await vmContext.terminate();
+    }
     return vmContext.interactiveExitCode;
   }