Betting on the stock market isn’t for the fainthearted. But it takes an iron constitution to buy in on Tesla. True, those who’ve hung with the automaker since its early days have been well rewarded. But recent years have taken investors on a rollercoaster ride. And nowhere has it been more apparent than over the past few months. After nearing a 52-week late last year, Tesla shares have been in decline. And that’s now showing signs of turning into a full-on rout, even some long-term Tesla bulls getting worried.