Unify and improve err/out implementation for node pthreads. NFC

We were overriding err in two different places.

The overridden version of node was not correctly formatting its
arguments. i.e. all objects were showing up as `[object Object]`

Author: sbc100

src/runtime_debug.js

@@ -209,8 +209,8 @@ function dbg(...args) {
 #if ENVIRONMENT_MAY_BE_NODE && PTHREADS
   // Avoid using the console for debugging in multi-threaded node applications
   // See https://github.com/emscripten-core/emscripten/issues/14804
-  if (ENVIRONMENT_IS_NODE && fs) {
-    fs.writeSync(2, args.join(' ') + '\n');
+  if (ENVIRONMENT_IS_NODE) {
+    err(...args);
   } else
 #endif
   // TODO(sbc): Make this configurable somehow.  Its not always convenient for

src/runtime_pthread.js

@@ -37,17 +37,6 @@ if (ENVIRONMENT_IS_PTHREAD) {
   // Thread-local guard variable for one-time init of the JS state
   var initializedJS = false;
 
-  function threadPrintErr(...args) {
-#if ENVIRONMENT_MAY_BE_NODE
-    // See https://github.com/emscripten-core/emscripten/issues/14804
-    if (ENVIRONMENT_IS_NODE) {
-      fs.writeSync(2, args.join(' ') + '\n');
-      return;
-    }
-#endif
-    console.error(...args);
-  }
-
 #if LOAD_SOURCE_MAP || USE_OFFSET_CONVERTER
   // When using postMessage to send an object, it is processed by the structured
   // clone algorithm.  The prototype, and hence methods, on that object is then
@@ -60,11 +49,6 @@ if (ENVIRONMENT_IS_PTHREAD) {
   }
 #endif
 
-#if expectToReceiveOnModule('printErr')
-  if (!Module['printErr'])
-#endif
-    err = threadPrintErr;
-
   // Turn unhandled rejected promises into errors so that the main thread will be
   // notified about them.
   self.onunhandledrejection = (e) => { throw e.reason || e; };

src/shell.js

@@ -390,8 +390,10 @@ if (!ENVIRONMENT_IS_AUDIO_WORKLET)
 var defaultPrint = console.log.bind(console);
 var defaultPrintErr = console.error.bind(console);
 if (ENVIRONMENT_IS_NODE) {
-  defaultPrint = (...args) => fs.writeSync(1, args.join(' ') + '\n');
-  defaultPrintErr = (...args) => fs.writeSync(2, args.join(' ') + '\n');
+  var utils = require('util');
+  var stringify = (a) => typeof a == 'object' ? utils.inspect(a) : a;
+  defaultPrint = (...args) => fs.writeSync(1, args.map(stringify).join(' ') + '\n');
+  defaultPrintErr = (...args) => fs.writeSync(2, args.map(stringify).join(' ') + '\n');
 }
 {{{ makeModuleReceiveWithVar('out', 'print',    'defaultPrint',    true) }}}
 {{{ makeModuleReceiveWithVar('err', 'printErr', 'defaultPrintErr', true) }}}

test/other/codesize/test_codesize_minimal_pthreads.gzsize

@@ -1 +1 @@
-4037
+4045

test/other/codesize/test_codesize_minimal_pthreads.jssize

@@ -1 +1 @@
-8374
+8382

test/test_other.py

@@ -15280,7 +15280,7 @@ def test_preload_module(self, args):
           assert(found);
         } else {
           int found = EM_ASM_INT(
-            err(sharedModules);
+            err('sharedModules:', sharedModules);
             return sharedModules['/library.so'] !== undefined;
           );
           assert(found);
@@ -15295,7 +15295,10 @@ def test_preload_module(self, args):
         return 0;
       }
     ''')
-    self.do_runf('main.c', 'done\n', emcc_args=['-sMAIN_MODULE=2', '--preload-file', 'tmp.so@library.so', '--use-preload-plugins'] + args)
+    expected = 'done\n'
+    if args:
+      expected = "sharedModules: { '/library.so': Module [WebAssembly.Module] {} }\ndone\n"
+    self.do_runf('main.c', expected, emcc_args=['-sMAIN_MODULE=2', '--preload-file', 'tmp.so@library.so', '--use-preload-plugins'] + args)
 
   @node_pthreads
   def test_standalone_whole_archive(self):