Fix the C4800 warnings.

test/testsymboldatabase.cpp

@@ -1675,9 +1675,9 @@ private:
 
     void symboldatabase42() { // only put variables in variable list
         GET_SYMBOL_DB("void f() { extern int x(); }\n");
-        ASSERT(db);
+        ASSERT(!!db);
         const Scope * const fscope = db ? db->findScopeByName("f") : NULL;
-        ASSERT(fscope);
+        ASSERT(!!fscope);
         ASSERT_EQUALS(0U, fscope ? fscope->varlist.size() : ~0U);  // "x" is not a variable
     }