Support field initializers and static/top-level fields in compile_with_dill_test

pkg/compiler/lib/src/kernel/element_map_impl.dart

Index: pkg/compiler/lib/src/kernel/element_map_impl.dart
diff --git a/pkg/compiler/lib/src/kernel/element_map_impl.dart b/pkg/compiler/lib/src/kernel/element_map_impl.dart
index 259fe5ea36b5c8943bc70969a018fce2a8c4de7b..7a29d03b2f46b094cf3dfd842cd14270c79edbb6 100644
--- a/pkg/compiler/lib/src/kernel/element_map_impl.dart
+++ b/pkg/compiler/lib/src/kernel/element_map_impl.dart
@@ -139,6 +139,11 @@ class KernelToElementMapImpl extends KernelToElementMapMixin {
     return _constantEnvironment.getConstantValue(constant);
   }
 
+  @override
+  ConstantValue getFieldConstantValue(ir.Field field) {
+    return getConstantValue(field.initializer, requireConstant: field.isConst);
+  }
+
   LibraryEntity lookupLibrary(Uri uri) {
     _KLibraryEnv libraryEnv = _env.lookupLibrary(uri);
     if (libraryEnv == null) return null;