Give the Method flag to the label-defs produced by TailRec.

This is consistent with those produced by the current pattern
matcher.

Author: sjrd

compiler/src/dotty/tools/dotc/transform/TailRec.scala

@@ -70,7 +70,7 @@ class TailRec extends MiniPhase with FullParameterization {
 
   override def runsAfter = Set(ShortcutImplicits.name) // Replaces non-tail calls by tail calls
 
-  final val labelFlags = Flags.Synthetic | Flags.Label
+  final val labelFlags = Flags.Synthetic | Flags.Label | Flags.Method
 
   /** Symbols of methods that have @tailrec annotatios inside */
   private val methodsWithInnerAnnots = new collection.mutable.HashSet[Symbol]()