[Kernel] replace function debuggable field with originalAsyncMarker field

pkg/kernel/lib/transformations/continuation.dart

Index: pkg/kernel/lib/transformations/continuation.dart
diff --git a/pkg/kernel/lib/transformations/continuation.dart b/pkg/kernel/lib/transformations/continuation.dart
index 112ea43b8274b3f3e182cc2e99039834e589fcb6..298e950455466178c308d3ac1609018404985f81 100644
--- a/pkg/kernel/lib/transformations/continuation.dart
+++ b/pkg/kernel/lib/transformations/continuation.dart
@@ -146,6 +146,7 @@ class SyncStarFunctionRewriter extends ContinuationRewriterBase {
       ..addAll(variableDeclarations())
       ..addAll([closureFunction, returnStatement]));
     enclosingFunction.body.parent = enclosingFunction;
+    enclosingFunction.originalAsyncMarker = enclosingFunction.asyncMarker;

[Kevin Millikin (Google), 2017/02/22 07:59:59]

It doesn't make sense to ever change the original async marker.  If we do that,
it might not be the original one (it's just the previous one).

I don't understand why we don't just leave it alone.

[jensj, 2017/02/22 10:36:45]

Done.

     enclosingFunction.asyncMarker = AsyncMarker.Sync;
     return enclosingFunction;
   }
@@ -698,6 +699,7 @@ class AsyncStarFunctionRewriter extends AsyncRewriterBase {
 
     enclosingFunction.body = new Block(statements);
     enclosingFunction.body.parent = enclosingFunction;
+    enclosingFunction.originalAsyncMarker = enclosingFunction.asyncMarker;

[Kevin Millikin (Google), 2017/02/22 07:59:59]

Same comment.

[jensj, 2017/02/22 10:36:45]

Done.

     enclosingFunction.asyncMarker = AsyncMarker.Sync;
     return enclosingFunction;
   }
@@ -820,8 +822,8 @@ class AsyncFunctionRewriter extends AsyncRewriterBase {
 
     enclosingFunction.body = new Block(statements);
     enclosingFunction.body.parent = enclosingFunction;
+    enclosingFunction.originalAsyncMarker = enclosingFunction.asyncMarker;

[Kevin Millikin (Google), 2017/02/22 07:59:59]

Same comment.

[jensj, 2017/02/22 10:36:45]

Done.

     enclosingFunction.asyncMarker = AsyncMarker.Sync;
-    enclosingFunction.debuggable = false;
     return enclosingFunction;
   }