Add test cases for #1944.

test/simple/test-util-inspect.js

@@ -62,3 +62,16 @@ assert.ok(ex.indexOf('[type]') != -1);
 // GH-1941
 // should not throw:
 assert.equal(util.inspect(Object.create(Date.prototype)), '{}')
+
+// GH-1944
+assert.doesNotThrow(function () {
+  var d = new Date();
+  d.toUTCString = null;
+  util.inspect(d);
+});
+
+assert.doesNotThrow(function () {
+  var r = /regexp/;
+  r.toString = null;
+  util.inspect(r);
+});