Fix a pthread stack corruption problem (#21417)

Fix a problem with pthread creation where it would call from JS to C/C++
function `_emscripten_thread_init()` before having correctly initialized
the C/C++ program stack, leading the pthread to stomp on the main
thread's stack for the execution of that function.

Author: juj

src/library_pthread.js

@@ -1063,8 +1063,12 @@ var LibraryPThread = {
 
   $establishStackSpace__internal: true,
   $establishStackSpace__deps: ['$stackRestore'],
-  $establishStackSpace: () => {
-    var pthread_ptr = _pthread_self();
+  $establishStackSpace: (pthread_ptr) => {
+#if ALLOW_MEMORY_GROWTH
+    // If memory growth is enabled, the memory views may have gotten out of date,
+    // so resync them before accessing the pthread ptr below.
+    updateMemoryViews();
+#endif
     var stackHigh = {{{ makeGetValue('pthread_ptr', C_STRUCTS.pthread.stack, '*') }}};
     var stackSize = {{{ makeGetValue('pthread_ptr', C_STRUCTS.pthread.stack_size, '*') }}};
     var stackLow = stackHigh - stackSize;

src/preamble.js

@@ -139,7 +139,7 @@ var HEAP,
 /* BigInt64Array type is not correctly defined in closure
 /** not-@type {!BigInt64Array} */
   HEAP64,
-/* BigUInt64Array type is not correctly defined in closure
+/* BigUint64Array type is not correctly defined in closure
 /** not-t@type {!BigUint64Array} */
   HEAPU64,
 #endif

src/runtime_pthread.js

@@ -179,21 +179,24 @@ if (ENVIRONMENT_IS_PTHREAD) {
         wasmPromiseResolve(msgData['wasmModule']);
 #endif // MINIMAL_RUNTIME
       } else if (cmd === 'run') {
+#if ASSERTIONS
+        assert(msgData['pthread_ptr']);
+#endif
+        // Call inside JS module to set up the stack frame for this pthread in JS module scope.
+        // This needs to be the first thing that we do, as we cannot call to any C/C++ functions
+        // until the thread stack is initialized.
+        establishStackSpace(msgData['pthread_ptr']);
+
         // Pass the thread address to wasm to store it for fast access.
         __emscripten_thread_init(msgData['pthread_ptr'], /*is_main=*/0, /*is_runtime=*/0, /*can_block=*/1, 0, 0);
 
+        PThread.receiveObjectTransfer(msgData);
+        PThread.threadInitTLS();
+
         // Await mailbox notifications with `Atomics.waitAsync` so we can start
         // using the fast `Atomics.notify` notification path.
         __emscripten_thread_mailbox_await(msgData['pthread_ptr']);
 
-#if ASSERTIONS
-        assert(msgData['pthread_ptr']);
-#endif
-        // Also call inside JS module to set up the stack frame for this pthread in JS module scope
-        establishStackSpace();
-        PThread.receiveObjectTransfer(msgData);
-        PThread.threadInitTLS();
-
         if (!initializedJS) {
 #if EMBIND
 #if PTHREADS_DEBUG