Fix gdextension_compat_hashes.cpp for double precision builds

[dsnopek]

Fixes #86346

I also added the class and method name to the message about mapping to non-existent hashes, since that's pretty critical information for debugging this sort of issue.

cc @Bromeon

[fire]

What sort of review are we looking for? I have a pet interest in double precision.

[dsnopek]

Ah, well, this is a little tricky to review. It's easy to see that running godot --dump-extension-api with a double precision build no longer prints out the ~40 warning messages. However, actually checking that the hash mappings are correct would be pretty tedious.

I made this PR by:

1. Compiling the engine with double precision on 6094738 (this is the commit before PR Fix method hashes with default arguments #81521 was merged, which fixed the hashing algorithm) and generating the extension_api.json
2. Compiling the engine with double precision on master and generating the extension_api.json
3. Processing the two files with a Python script to figure out the hash mapping and generate some code in a text file
4. Manually going through gdextension_compat_hashes.cpp and copy-pasting the code in where needed with the addition of the #ifdef's

So, to really check it, you'd need to generate the two extension_api.json files and go through each one, which I'm not sure is something anyone would really be willing to do :-)

It may be easiest to approve/merge based on the warnings having gone away, and then we can fix any issues if users find any?

[fire]

Approve/merge based on the warnings having gone away, and then we can fix any issues if users find any?

Sure!

[akien-mga]

Thanks!

[akien-mga]

Cherry-picked for 4.2.2.