2025-05: add Array.fromAsync Stage 4 and BigInt Math Stage 2

Please note that the proposal-array-from-async proposal is out of date and still has a pending pull request (tc39/proposal-array-from-async#50). 

The most up-to-date version is the tc39/ecma262#3581 pull request linked in the table.

Author: js-choi

2025/05.md

@@ -112,6 +112,8 @@ When applicable, use these emoji as a prefix to the agenda item topic.
 
     | stage | timebox | topic | presenter |
     |:-----:|:-------:|-------|-----------|
+    | 2 | 30 m | [BigInt Math](https://github.com/tc39/proposal-bigint-math/) for Stage 2 | J. S. Choi |
+    | 4 | 30 m | Array.fromAsync for Stage 4 ([spec pull request](https://github.com/tc39/ecma262/pull/3581)) | J. S. Choi |
 
 1. Longer or open-ended discussions
 
@@ -142,6 +144,7 @@ When applicable, use these emoji as a prefix to the agenda item topic.
 
 <!-- Constraints supplied more than three days before the meeting should go here -->
 - Samina would prefer the "ECMA Framework" topic to be discussed on Day 2 to give people time to mull it over and bring any questions or doubts the following day.
+- J. S. Choi is unavailable until 15:00 (GMT+2) on all days and would strongly prefer 05-28 or 05-29 over 05-30.
 
 #### Late-breaking Schedule Constraints