Avoid MSVC's C6323 warning (use of arithmetic operator on Boolean type)

src/runtime/runtime-scopes.cc

Index: src/runtime/runtime-scopes.cc
diff --git a/src/runtime/runtime-scopes.cc b/src/runtime/runtime-scopes.cc
index 2a0b435872b67d5ef7a553b480cb9007fba1cc4e..352e9efdf0b2c85beed23f4221fee4056df22027 100644
--- a/src/runtime/runtime-scopes.cc
+++ b/src/runtime/runtime-scopes.cc
@@ -106,7 +106,8 @@ RUNTIME_FUNCTION(Runtime_DeclareGlobals) {
     bool is_var = initial_value->IsUndefined();
     bool is_const = initial_value->IsTheHole();
     bool is_function = initial_value->IsSharedFunctionInfo();
-    DCHECK(is_var + is_const + is_function == 1);
+    DCHECK_EQ(1,
+              BoolToInt(is_var) + BoolToInt(is_const) + BoolToInt(is_function));
 
     Handle<Object> value;
     if (is_function) {
@@ -220,7 +221,8 @@ RUNTIME_FUNCTION(Runtime_DeclareLookupSlot) {
   bool is_var = *initial_value == NULL;
   bool is_const = initial_value->IsTheHole();
   bool is_function = initial_value->IsJSFunction();
-  DCHECK(is_var + is_const + is_function == 1);
+  DCHECK_EQ(1,
+            BoolToInt(is_var) + BoolToInt(is_const) + BoolToInt(is_function));
 
   int index;
   PropertyAttributes attributes;