Fix NumberFormatException with very large numbers in ArrayMap

[veeti]

Test case names containing long numbers could result in a NumberFormatException being thrown. Support arbitrarily large numbers by comparing strings.

[nedtwigg]

IIUC, this helps once there are more than 2,147,483,647 snapshots.

If each snapshot has size of only 1 byte, this would be ~2Gb of snapshot data (not counting indirection). I would guess ~10GB in RAM, even if the data was only a single byte being snapshotted.

Do you have a usecase where you need this? How did you choose to work on this change?

[veeti]

I am hitting this from my Kotest suite. This reproducer should demonstrate:

class ArrayMapNumberFormatTest : DescribeSpec({
    it("a123") {}
    it("a${Long.MAX_VALUE}") {}
})