I have no idea if this actually happened or not. However, I do know that I have read about it before, and when I went to look for some cites, I found references to it in books from the modern times all the way back to the 1800s. Some are tales (or histories of sorts) about such-and-such from some particular place, though the stories are obviously not firsthand. Anyway, the point is, the stories at least can be cited. That’s not quite what the OP asked for, but it’s a step in the right direction.
The Sea-king: A Metrical Romance, in Six Cantos, with Notes, Historical and Illustrative (1848)
The Religion of the Northmen (1854)
The Book of Firsts: 150 World-Changing People and Events from Caesar Augustus to the Internet (2010)
Ideology and Power in the Viking and Middle Ages (2011)
The Farfarers: A New History of North America (2011)
Wayward Heroes (2016)
The Sea King has this:
If the book is to be believed, the practice was common.
The Religion of the Northmen refers to vikings as “heathens” and “Norwegian Vikings in heathendom”, and so might be a bit biased, but claims that the practice wasn’t just savage cruelty, but was also an offering of human sacrifice to Odin.
The Book of Firsts refers to a Viking who was teasingly dubbed “Child-Friend” because unlike the other Vikings, he did not throw babies into the air and catch them on the end of his spear. This story at least has some consistencies with Olver mentioned in The Sea King. There is some consistency in that different books do refer to Vikings who did not engage in this practice as being viewed as weak in the eyes of their peers.
The Farfarers gives the detail that the Vikings stood in a circle, and tossed the babies from one spear to another, catching it and tossing it across the circle over and over.
Wayward Heroes also mentions that the babies were considered offerings to Odin, and states that the Vikings considered it “wholesome” when the child’s mother had been beheaded or captured, and the father killed, and the homes burned to the ground. I suppose in that sense, rather than leave defenseless babies to die from exposure when there was no one left to take care of them, they sacrificed them to Odin instead. It’s horrific by modern standards, but it seems a bit more justified than spearing infants merely for sport, as other references imply.
So, there you go. That’s what the books say. It was either a sport of sorts where Viking warriors would stand around in the circle and spear-chuck the baby back and forth, or it was an offering to Odin, or perhaps both, or something else altogether. And they are all stories. I did not see any firsthand accounts in any of the books, nor have I seen any elsewhere.
My own take on this (which is taking a hard left turn into IMHO territory) is that there is enough consistency between the stories for me to think that there is some truth to it all. Exactly what that truth is, I have no idea though.