Fix missed merge conflict for merge request https://github.com/dart-lang/sdk/issues/24782

pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart

Index: pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart
diff --git a/pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart b/pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart
index 687bea37bba9660b4c44a708acc4b29478061ae1..8ac784ae036f845c03aa2f616559a3803a4d09be 100644
--- a/pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart
+++ b/pkg/compiler/lib/src/js_emitter/program_builder/program_builder.dart
@@ -423,7 +423,7 @@ class ProgramBuilder {
                   functionType = returnType;
                 } else if (returnType.treatAsDynamic ||
                     _compiler.types.isSubtype(returnType,
-                        backend.coreTypes.functionType)) {
+                        backend.resolution.coreTypes.functionType)) {
                   if (returnType.isTypedef) {
                     TypedefType typedef = returnType;
                     // TODO(jacobr): can we just use typdef.unaliased instead?