[parser] implement error reporting for Scanner errors

test/message/unicode-escape-undefined.out

Index: test/message/unicode-escape-undefined.out
diff --git a/test/fuzzer/fuzzer.status b/test/message/unicode-escape-undefined.out
similarity index 54%
copy from test/fuzzer/fuzzer.status
copy to test/message/unicode-escape-undefined.out
index df922bbf4e6d398165322c804085e757128071c9..9b0483cdcc9cfd76da9a9719aabd3875d691fa67 100644
--- a/test/fuzzer/fuzzer.status
+++ b/test/message/unicode-escape-undefined.out
@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-[
-
-]
+*%(basename)s:5: SyntaxError: Undefined Unicode code-point
+print("\u{110000}");
+       ^^^^^^^^^
+SyntaxError: Undefined Unicode code-point