Refactor LoopHandler to avoid calling KernelAstAdapter.getNode

pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart

Index: pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
diff --git a/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart b/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
index 94fb3f53d68140e28b9819b04f20caee0b7e7bae..b80d52cdaf8cb0256684fa94749e98b74a8cdf91 100644
--- a/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
+++ b/pkg/compiler/lib/src/ssa/kernel_ast_adapter.dart
@@ -322,6 +322,12 @@ class KernelAstAdapter extends KernelToElementMapMixin
   Spannable getSpannable(MemberEntity member, ir.Node node) {
     return getNode(node);
   }
+
+  @override
+  LoopClosureRepresentationInfo getClosureRepresentationInfoForLoop(
+      ClosureClassMaps closureClassMaps, ir.TreeNode node) {
+    return closureClassMaps.getClosureRepresentationInfoForLoop(getNode(node));
+  }
 }
 
 /// Visitor that converts kernel dart types into [ResolutionDartType].