Stop reporting error when not parsing function bodies (issue 23460)

pkg/analyzer/lib/src/generated/parser.dart

Index: pkg/analyzer/lib/src/generated/parser.dart
diff --git a/pkg/analyzer/lib/src/generated/parser.dart b/pkg/analyzer/lib/src/generated/parser.dart
index 2e5bca214d79e8ecb542d8ad8eb44e24ea7f385f..29974682eaaa61b81bd3fb6ff3e4a24a9d367556 100644
--- a/pkg/analyzer/lib/src/generated/parser.dart
+++ b/pkg/analyzer/lib/src/generated/parser.dart
@@ -5066,7 +5066,9 @@ class Parser {
           externalKeyword == null) {
         _reportErrorForToken(ParserErrorCode.CONST_FACTORY, factoryKeyword);
       } else if (body is EmptyFunctionBody) {
-        if (factoryKeyword != null && externalKeyword == null) {
+        if (factoryKeyword != null &&
+            externalKeyword == null &&
+            _parseFunctionBodies) {
           _reportErrorForToken(
               ParserErrorCode.FACTORY_WITHOUT_BODY, factoryKeyword);
         }