[Ruby] Message#hash crashes with a C assertion on Windows

[dazuma]

What version of protobuf and what language are you using?
Version: 3.15.8
Language: Ruby 2.7.3, 3.0.1

What operating system (Linux, Windows, ...) and version?
Windows Server 2019 (10.0.17763), via the "windows-latest" platform on GitHub Actions.

What runtime / compiler are you using (e.g., python version or gcc version)
n/a (using the binary gem release)

What did you do?

require "google/protobuf"

Google::Protobuf::DescriptorPool.generated_pool.build do
  add_file("windoze.proto", :syntax => :proto3) do
    add_message "windoze.SimpleTest" do
      # Note: No fields necessary
    end
  end
end
module Windoze
  SimpleTest = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("windoze.SimpleTest").msgclass
end

message = Windoze::SimpleTest.new
puts message.hash

What did you expect to see
An integer hash value displayed

What did you see instead?
The Ruby VM terminates with the following assertion coming from C code:

[BUG] Unnormalized Fixnum value 0xbb5cc1f7724449a5

Anything else we should know about your project / environment

I found this while investigating #8554. The assertion is coming from here and seems to happen if the value claims to be a Fixnum but doesn't fall within the range of the long type. Thus, it could trigger on 64-bit Windows where longs are 32 bits, if the Fixnum is set from a 64-bit value. This is indeed the case in Message_hash, which takes a 64-bit integer from wyhash, and crams it directly into INT2FIX.

This does not seem to trigger on Linux or MacOS, which is unsurprising because long is 64-bit on those platforms.