if (!stmt->down) tc->flags &= ~TCF_TOP_LEVEL;
js_PushStatement(JSTreeContext *tc, JSStmtInfo *stmt, JSStmtType type,		 ptrdiff_t top){    stmt->type = type;    SET_STATEMENT_TOP(stmt, top);    stmt->label = NULL;    stmt->down = tc->topStmt;    tc->topStmt = stmt;}