Improved handling of unhandled promise rejections with no error in Node

* Fixes #1759

src/core/GlobalErrors.js

@@ -17,7 +17,22 @@ getJasmineRequireObj().GlobalErrors = function(j$) {
     this.jasmineHandlers = {};
     this.installOne_ = function installOne_(errorType, jasmineMessage) {
       function taggedOnError(error) {
-        error.jasmineMessage = jasmineMessage + ': ' + error;
+        var substituteMsg;
+
+        if (error) {
+          error.jasmineMessage = jasmineMessage + ': ' + error;
+        } else {
+          substituteMsg = jasmineMessage + ' with no error or message';
+
+          if (errorType === 'unhandledRejection') {
+            substituteMsg +=
+              '\n' +
+              '(Tip: to get a useful stack trace, use ' +
+              'Promise.reject(new Error(...)) instead of Promise.reject().)';
+          }
+
+          error = new Error(substituteMsg);
+        }
 
         var handler = handlers[handlers.length - 1];