Don't redirect dbg to threadPrintErr (#23879)

The redirection to node's stderr is already part of `dbg` so there is no
need to redirect it here.

Also, we don't necessarily want to send dbg message to console.error.

Fixes: #23860

Author: sbc100

src/runtime_pthread.js

@@ -38,15 +38,14 @@ if (ENVIRONMENT_IS_PTHREAD) {
   var initializedJS = false;
 
   function threadPrintErr(...args) {
-    var text = args.join(' ');
 #if ENVIRONMENT_MAY_BE_NODE
     // See https://github.com/emscripten-core/emscripten/issues/14804
     if (ENVIRONMENT_IS_NODE) {
-      fs.writeSync(2, text + '\n');
+      fs.writeSync(2, args.join(' ') + '\n');
       return;
     }
 #endif
-    console.error(text);
+    console.error(...args);
   }
 
 #if LOAD_SOURCE_MAP || USE_OFFSET_CONVERTER
@@ -65,9 +64,6 @@ if (ENVIRONMENT_IS_PTHREAD) {
   if (!Module['printErr'])
 #endif
     err = threadPrintErr;
-#if ASSERTIONS || RUNTIME_DEBUG
-  dbg = threadPrintErr;
-#endif
   function threadAlert(...args) {
     var text = args.join(' ');
     postMessage({cmd: 'alert', text, threadId: _pthread_self()});

test/other/codesize/test_codesize_minimal_pthreads.gzsize

@@ -1 +1 @@
-4113
+4108

test/other/codesize/test_codesize_minimal_pthreads.jssize

@@ -1 +1 @@
-8551
+8550