test_pthread_join_and_asyncify fails on asan/lsan

`asan.test_pthread_join_and_asyncify` fails with the message
```console
worker.js onmessage() captured an uncaught exception: RuntimeError: null function or function signature mismatch
RuntimeError: null function or function signature mismatch
at test_pthread_join_and_asyncify.wasm.__asan::asan_thread_start(void*) (wasm://wasm/test_pthread_join_and_asyncify.wasm-00a319e6:wasm-function[571]:0x18984)
at Object.invokeEntryPoint (/usr/local/google/home/aheejin/emscripten/out/test/test_pthread_join_and_asyncify.js:1465:37)
at handleMessage (/usr/local/google/home/aheejin/emscripten/out/test/test_pthread_join_and_asyncify.worker.js:164:35)
at MessagePort. (/usr/local/google/home/aheejin/emscripten/out/test/test_pthread_join_and_asyncify.worker.js:29:38)
at [nodejs.internal.kHybridDispatch] (node:internal/event_target:810:20)
at exports.emitMessage (node:internal/per_context/messageport:23:28)
```
`lsan.test_pthread_join_and_asyncify` fails in a similar way with only the function name (`asan_thread_start`) different.

This doesn't look related to #21663 because they fail without it too.

Our Test suite CI (https://ci.chromium.org/ui/p/emscripten-releases/builders/luci.emscripten-releases.ci/linux-test-suites) doesn't detect it because this test is only enabled with Node Canary and skipped in the CI.

---

I'm not very familiar with how JSPI and sanitizers work, but looking at the generated code, within `asan_thread_start`, there is a `call_indirect`. Here `(type $3)` is `(param i32) (result i32)`
```wast
(call_indirect (type $3)
(i32.load offset=12
(local.get $1)
)
(i32.load offset=8
(local.get $1)
)
)
```
which I think is supposed to call `run_thread` here:
https://github.com/emscripten-core/emscripten/blob/9293ec8eb9e717bddf495247ebefd452b5a53ca1/test/core/test_pthread_join_and_asyncify.c#L25
https://github.com/emscripten-core/emscripten/blob/9293ec8eb9e717bddf495247ebefd452b5a53ca1/test/core/test_pthread_join_and_asyncify.c#L17
And `run_thread`'s type is `(param i32) (result i32)`.

But the actual function called by that `call_indirect`, which is in the `elem` section, is a function named `$export$run_thread`. And its signature is `(param $susp externref) (param $0 i32) (result i32)`. (Note that there is an additional `externref` param)

I think this is the reason why it fails with the "signature mismatch" error. I'm not familiar with how JSPI works, so I'm not sure why `run_thread` is exported with a different signature.

cc @brendandahl