Glob-style require doesn't resolve extension correctly

Thanks for building the glob require feature, it's much appreciated! I noticed a small bug i'd like to share.

For `require("./chunks/" + id)` where `id` is a module name without extension, esbuild produces a bundle that results in `Module not found in bundle: ./chunks/abcde`. Here's a code example: [ESBuild Playground](https://esbuild.github.io/try/#YgAwLjE5LjIALS1idW5kbGUAZQBlbnRyeS5qcwBjb25zdCBfX3dlYnBhY2tfcmVxdWlyZV9fID0gewogIHUoY2h1bmtJZCkgewogICAgcmV0dXJuIHsgNDI6ICJhYmNkZSIgfVtjaHVua0lkXQogIH0KfQoKZnVuY3Rpb24gcnVuRW50cnlQb2ludChjaHVua0lkKSB7CiAgcmVxdWlyZSgiLi9jaHVua3MvIiArIF9fd2VicGFja19yZXF1aXJlX18udShjaHVua0lkKSkKfQoKcnVuRW50cnlQb2ludCg0MikAAGNodW5rcy9hYmNkZS5qcwBjb25zb2xlLmxvZygiSGVsbG8gV29ybGQhIikKbW9kdWxlLmV4cG9ydHMgPSA0Mg
).

Without bundling, Node resolves this correctly, and it's a pattern Webpack likes to emit - so I'd consider it a bug within esbuild.

I believe the cause is that the `__glob` snippet generated by esbuild doesn't correctly mimic Node's resolution strategy. Here's a sketch of how it might be fixed:

```diff
var __glob = (map) => (path) => {
- var fn = map[path];
+ var fn = map[path] ?? map[path + '.js'] ?? map[path + '/index.js'];
if (fn)
return fn();
throw new Error("Module not found in bundle: " + path);
};
```

[Node's full resolution strategy](https://nodejs.org/api/modules.html#all-together) is a little more nuanced, but i'm sure there's a tradeoff to be made here between simplicity and spec-completeness :)

I'd be open to contribute a fix for the issue, please let me know if you're interested in that.

Start with the linked esbuild Playground and inspect the generated __glob helper and glob-style require handling. Verify extensionless ./chunks/abcde resolution against the reported case; done means the bundled output loads chunks/abcde.js instead of throwing.

Written by the indexing model from the issue text.