Address some CodeQL warnings

src/statement.cc

@@ -840,6 +840,10 @@ void Statement::GetRow(Row* row, sqlite3_stmt* stmt) {
     for (int i = 0; i < cols; i++) {
         int type = sqlite3_column_type(stmt, i);
         const char* name = sqlite3_column_name(stmt, i);
+        if (name == NULL) {
+            assert(false);
+        }
+
         switch (type) {
             case SQLITE_INTEGER: {
                 row->push_back(new Values::Integer(name, sqlite3_column_int64(stmt, i)));

src/statement.h

@@ -86,7 +86,7 @@ class Statement : public Napi::ObjectWrap<Statement> {
             callback.Reset(cb_, 1);
         }
         virtual ~Baton() {
-            for (unsigned int i = 0; i < parameters.size(); i++) {
+            for (size_t i = 0; i < parameters.size(); i++) {
                 Values::Field* field = parameters[i];
                 DELETE_FIELD(field);
             }