win: Remove workaround for clang-cl that's no longer necessary.

src/shared/platform/win/nacl_secure_random.c

Index: src/shared/platform/win/nacl_secure_random.c
diff --git a/src/shared/platform/win/nacl_secure_random.c b/src/shared/platform/win/nacl_secure_random.c
index b73766fccf702e3f0891e4dac1477fb55e9256fc..f549441bab6d784d74a7fa1063ed5a2012cb8fab 100644
--- a/src/shared/platform/win/nacl_secure_random.c
+++ b/src/shared/platform/win/nacl_secure_random.c
@@ -9,14 +9,6 @@
  */
 #include <windows.h>
 
-/* Work around a clang-cl bug: SecureZeroMemory() below uses __stosb() but
- * windows.h only declares that intrinsic and then uses `#pragma intrinsic` for
- * it.  clang-cl doesn't implement `#pragma intrinsic` yet; it instead defines
- * the function as an always-inline symbol in its intrin.h.
- * TODO(thakis): Remove this once http://llvm.org/PR19898 is fixed.
- */
-#include <intrin.h>
-
 /*
  * #define needed to link in RtlGenRandom(), a.k.a. SystemFunction036. See
  * the "Community Additions" comment on MSDN here: