exit pthread properly on node [ci skip]

Author: kripken

src/library_pthread.js

@@ -937,6 +937,11 @@ console.log('  postedded');
     else PThread.threadExit(status);
 #if WASM_BACKEND
     // pthread_exit is marked noReturn, so we must not return from it.
+    if (ENVIRONMENT_HAS_NODE) {
+      // exit the pthread properly on node, as a normal JS exception will halt
+      // the entire application.
+      process.exit(status);
+    }
     throw 'pthread_exit';
 #endif
   },