function/stdlib: the Modulo function panics if the first argument is an infinity about go-cty

[apparentlymart]

I've narrowed down the cause of this to actually be inside Value.Modulo rather than in the modulo function. Specifically it seems to originate here:

go-cty/cty/value_ops.go

Lines 693 to 694 in 47a7961

	rat := val.Divide(other)
	ratFloorInt, _ := rat.v.(*big.Float).Int(nil)

There's apparently some input that makes Divide return an infinity here, which then causes big.Float.Int to return nil, which in turn panics later on while trying to make use of that int.

Value.Modulo is already trying to catch and handle all of the situations that might make Divide return zero, so I don't have a reproduction case with which to understand what input it isn't catching, and so I'm hesitant to just patch over it without knowing what the intended operation was and thus what the result ought to have been.