It's got glucose syrup, water, and FC&C dye, usually red 5 and yellow 6.
It's not HFCS - that's about 55-75% fructose, and that wouldn't do. It's not sugar, that's sucrose, or 50% glucose and 50% fructose.
I suspect the origin of the glucose syrup is corn b/c that's where most glucose syrup comes from, but I don't have evidence for that. It's just a feelin'.
I am sceptical of any scheme to come up with a sugar alternative to the test with orange juice, jelly beans, etc. b/c the test is supposed to check clearance of glucose. If you put any slower-metabolizing fructose in the test, you might be altered, higher results, making the test be false-positive.