Fix Windows build.

src/hydrogen-gvn.h

Index: src/hydrogen-gvn.h
diff --git a/src/hydrogen-gvn.h b/src/hydrogen-gvn.h
index 3da3ecfbf085a5e940b7f432a4db323a3079f503..cb83354a7e16217311798a10b8d8cf90969a181f 100644
--- a/src/hydrogen-gvn.h
+++ b/src/hydrogen-gvn.h
@@ -44,7 +44,9 @@ class SideEffects V8_FINAL {
  public:
   static const int kNumberOfSpecials = 64 - kNumberOfFlags;
 
-  SideEffects() : bits_(0) {}
+  SideEffects() : bits_(0) {
+    ASSERT(kNumberOfFlags + kNumberOfSpecials == sizeof(bits_) * CHAR_BIT);
+  }
   explicit SideEffects(GVNFlagSet flags) : bits_(flags.ToIntegral()) {}
   bool IsEmpty() const { return bits_ == 0; }
   bool ContainsFlag(GVNFlag flag) const {
@@ -74,7 +76,6 @@ class SideEffects V8_FINAL {
   }
 
   uint64_t bits_;
-  STATIC_ASSERT(kNumberOfFlags + kNumberOfSpecials == sizeof(bits_) * CHAR_BIT);
 };