Fix: handle absent crypto, fixes #19100

[mihailik]

Fixes #19100

[sheetalkamat]

I am assuming we dont want to make it optional in tsserver.
(checkout https://github.com/Microsoft/TypeScript/blob/master/src/server/editorServices.ts#L408)

[mihailik]

@sheetalkamat do you think it's a good idea to allow running tsserver without crypto too?

[mhegazy]

We have too many assumptions that if --watch is allowed we can use hashes. just checking here is not sufficient i am afraid.

[mihailik]

@mhegazy let's calculate a weak hash in code

[mhegazy]

sure

[mihailik]

@mhegazy just to check: collisions due to weak hash are only affecting performance, cannot cause incorrect behaviour, is that right?

[mhegazy]

that is my expectation as well.

[mhegazy]

closing for now. please reopen with a default implementation for a weak hash function.