Address review comments

Author: kleisauke

src/postamble.js

@@ -449,6 +449,9 @@ function exit(status, implicit) {
 function procExit(code) {
   EXITSTATUS = code;
   if (!keepRuntimeAlive()) {
+#if USE_PTHREADS
+    PThread.terminateAllThreads();
+#endif
 #if expectToReceiveOnModule('onExit')
     if (Module['onExit']) Module['onExit'](code);
 #endif

tests/test_core.py

@@ -2325,7 +2325,7 @@ def test_pthread_dispatch_after_exit(self):
 
   @node_pthreads
   def test_pthread_atexit(self):
-    # Test whether we can terminate a running thread during atexit.
+    # Test to ensure threads are still running when atexit-registered functions are called
     self.set_setting('EXIT_RUNTIME')
     self.set_setting('PTHREAD_POOL_SIZE', 1)
     self.do_run_in_out_file_test('pthread/test_pthread_atexit.c')