The S&P 500 and especially the Nasdaq fell below their 50-day moving averages. But the Dow Jones and Russell 2000 hit new highs Thursday, though they came off their best levels. Micron Technology (MU) soared on blowout earnings and guidance, lifting Sandisk (SNDK) and a variety of AI hardware plays. But Apple (AAPL) tumbled after hiking prices due to memory…