Fix infinite loop: module.exports alias detection

[sandersn]

Previously, module.exports alias detection in the binder could enter an
infinite recursion. Now it does not.

Notably, there are two safeguards: a counter limiter that I set at
100, and an already-seen set. I actually prefer the counter limiter code
because it's foolproof and uses less memory. But it takes 100
iterations to escape from loops.

I want to only keep one safeguard. Opinions? Should I reduce the number of allowed iterations?

Fixes #31094

[sandersn]

I decided on the counter-based limit since it uses less memory and is just as fast in the common case. It's also dead simple.

[rbuckton]

@sandersn: You could set a NodeFlag or some other bit as you start to check the node, exit if the bit is already set, and unset the bit when you exit the function (so that it is unset if the node is reused in incremental parse).

[sandersn]

@rbuckton reusing existing memory is really clever! I do like the simplicity of a counter though, so I think I'll stick with that.