[PATCH] [ASan] Fix MSVC -W3 warnings when building the Windows RTL

[Kostya Serebryany]

  All others look ok, but please check linux build.


================
Comment at: asan/asan_fake_stack.h:26
@@ -25,3 +25,3 @@
   u64 real_stack     : 48;
-  u64 size_minus_one : 16;
+  uptr size_minus_one : 16;
   // End of the first 32 bytes.
----------------
You can't do it like this with a bitfield


http://llvm-reviews.chandlerc.com/D885