Someone else would certainly buy them. The brand is too good to let it vanish. So it's just a matter of price -- the more indebted is Tesla the more likely someone would buy it.
Tesla as a brand will certainly continue to exist.
Alas: that's not what is being discussed. If Tesla were to enter bankruptcy, then it legally is no longer necessary to uphold its end of any bonds, payments, or other such financial issues.
Tesla might go bankrupt in the next few years, if this Model 3 thing doesn't work out. At which point, it won't return any of the money from these reservations.
I think it is extremely unlikely Tesla would go bankrupt in the next few years. If it has a cash flow problem, then it just needs a loan or investment. There are lots of venture capitalists out there who bet all the time on companies that might not succeed but could make a ton of money if they did, and Tesla certainly fits that description.
Now it is true that Musk would hate to do this, because it would mean giving up some independence, but if necessary he no doubt will.
I think the real reason we are seeing all these claims that Tesla is about to go under is that there is about $10 billion bet on stock shorts that is going to explode in the near future, and so the financiers are desperately trying to put a scare into people and drive down the stock price.