When Elon Musk asked his Twitter followers last weekend if he should sell 10 percent of his Tesla Inc stock, he said he was posing the question because “much is made lately of unrealized gains being a means of tax avoidance.” Yet the timing of his upcoming stock sale could solve a major tax headache for himself and save Tesla billions of dollars from its own tax bill before congressional Democrats clamp down on such breaks and try to hike taxes for the super-wealthy, tax and corporate compensation experts said. Musk could time the proposed sale to coincide with a federal tax bill of nearly $11 billion that would be triggered by exercising a chunk of his Tesla stock options worth $26.6 billion as of Monday’s close. The options expire in August 2022 and Musk has said previously he does not keep much cash around, because his wealth is tied …