Try to fix the MSVC build.

0xFFFFFFFFFFFFFFFFLL doesn't fit in a long long so it should have
type 'unsigned long long'. MSVC thinks it's a (signed) __int64.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228950 91177308-0d34-0410-b5e6-96231b3b80d8

unittests/Support/MathExtrasTest.cpp

@@ -148,7 +148,7 @@ TEST(MathExtras, countLeadingOnes) {
   }
   for (int i = 62; i >= 0; --i) {
     // Start with all ones and unset some bit.
-    EXPECT_EQ(63u - i, countLeadingOnes(0xFFFFFFFFFFFFFFFFLL ^ (1LL << i)));
+    EXPECT_EQ(63u - i, countLeadingOnes(0xFFFFFFFFFFFFFFFFULL ^ (1LL << i)));
   }
   for (int i = 30; i >= 0; --i) {
     // Start with all ones and unset some bit.