changed lcm and gcd implementations for when just one arg is infinite

[Priynsh]

Fixes #56991 by adding conditions for both gcd and lcm cases. Also fixes tests for the same i.e. lot of tests regarding gcdx and lcm are removed. Two relevant tests have been added as well.

[LilithHafner]

Thanks! Looking at this I'm realizing there is another way to define lcm and gcd that allows lcm(1//1, 1//0), and possibly even lcm(0//1, 1//0) to be well-defined.

Currently, we define

a is a multiple of b if there exists an integer m such that a=mb.

If we change that to

a is a multiple of b if there exists an integer or 1//0 or false m such that a=mb.

Then the following are correct:

julia> lcm(1//0, 1//1)
1//0 # currently 1//1

julia> lcm(1//0, 0//1)
0//1 # current behavior, only correct with #57068, otherwise error is appropriate

julia> gcd(1//0, 1//1)
1//1 # currently 1//0

julia> gcd(1//0, 0//1)
1//0 # current behavior, only correct with #57068, otherwise error is appropriate