[parser] report invalid rest parameter errors in Arrow functions

test/message/arrow-invalid-rest-2.out

Index: test/message/arrow-invalid-rest-2.out
diff --git a/test/message/arrow-invalid-rest-2.out b/test/message/arrow-invalid-rest-2.out
new file mode 100644
index 0000000000000000000000000000000000000000..0196483a66e910607e28cd5d5058bbb0b7ab011c
--- /dev/null
+++ b/test/message/arrow-invalid-rest-2.out
@@ -0,0 +1,4 @@
+*%(basename)s:7: SyntaxError: Rest parameter must be an identifier or destructuring pattern
+var f = (a, ...x = 10) => x;
+            ^^^^^^^^^
+SyntaxError: Rest parameter must be an identifier or destructuring pattern