console: treat non-strings as separate argument in console.assert()

fixes nodejs#49680

PR-URL: nodejs#49722
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>

lib/internal/console/constructor.js

@@ -430,9 +430,14 @@ const consoleMethods = {
     this.error(err.stack);
   },
 
+  // Defined by: https://console.spec.whatwg.org/#assert
   assert(expression, ...args) {
     if (!expression) {
-      args[0] = `Assertion failed${args.length === 0 ? '' : `: ${args[0]}`}`;
+      if (args.length && typeof args[0] === 'string') {
+        args[0] = `Assertion failed: ${args[0]}`;
+      } else {
+        ArrayPrototypeUnshift(args, 'Assertion failed');
+      }
       // The arguments will be formatted in warn() again
       ReflectApply(this.warn, this, args);
     }

test/message/console_assert.js

@@ -0,0 +1,5 @@
+'use strict';
+
+require('../common');
+
+console.assert(false, Symbol('hello'));

test/message/console_assert.out

@@ -0,0 +1 @@
+Assertion failed* Symbol(hello)