Merge to upstream r225300.

Change-Id: I2b23715db9ac129ff80aa78ad5824db0a4d6fbb3

test/std/numerics/rand/rand.predef/mt19937.pass.cpp

@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <random>
+
+// typedef mersenne_twister_engine<uint_fast32_t, 32, 624, 397, 31,
+//                                 0x9908b0df,
+//                                 11, 0xffffffff,
+//                                 7,  0x9d2c5680,
+//                                 15, 0xefc60000,
+//                                 18, 1812433253>                      mt19937;
+
+#include <random>
+#include <cassert>
+
+int main()
+{
+    std::mt19937 e;
+    e.discard(9999);
+    assert(e() == 4123659995u);
+}