Revert "[WebAssembly] Temporarily work around lack of __attribute__((constructor))"

This reverts commit 8ef9f7f.

Author: DougGregor

stdlib/public/runtime/ProtocolConformance.cpp

@@ -1392,17 +1392,8 @@ static bool swift_isInConformanceExecutionContextImpl(
     return true;
 
   if (context->globalActorIsolationType) {
-    if (!_swift_task_isCurrentGlobalActorHook) {
-#if defined(__wasm__)
-      // FIXME: We don't currently support a concurrency model for WebAssembly,
-      // and the global actor hook isn't getting initialized due to the
-      // lack of __attribute__((constructor)) support. Therefore, we
-      // treat everything "as if" it were on the correct global actor.
-      return true;
-#else
+    if (!_swift_task_isCurrentGlobalActorHook)
       return false;
-#endif
-    }
 
     // Check whether we are running on this global actor.
     if (!_swift_task_isCurrentGlobalActorHook(