[Bug #21211]

Socket errors raised from background threads are hard to track down because
their backtrace starts from the spawned thread.

To solve this we can raise a new error with the old one as `cause`.

[Bug #21179]

```
socket.rb:1046:in 'Socket::HostnameResolutionStore#get_addrinfo': can not access non-shareable objects in constant
Socket::HostnameResolutionStore::PRIORITY_ON_V6 by non-main ractor. (Ractor::IsolationError)
	from socket.rb:724:in 'block in Socket.tcp_with_fast_fallback'
	from socket.rb:720:in 'Socket.tcp_with_fast_fallback'
```

	Do not save ResolutionError if resolution succeeds for any address family (#12678)

	* Do not save ResolutionError if resolution succeeds for any address family

	Socket with Happy Eyeballs Version 2 performs connection attempts and name resolution in parallel.

	In the existing implementation, if a connection attempt failed for one address family while name resolution was still in progress for the other, and that name resolution later failed, the method would terminate with a name resolution error.
	This behavior was intended to ensure that the final error reflected the most recent failure, potentially overriding an earlier error.

	However, [Bug #21088](https://bugs.ruby-lang.org/issues/21088) made me realize that terminating with a name resolution error is unnatural when name resolution succeeded for at least one address family.

	This PR modifies the behavior so that if name resolution succeeds for one address family, any name resolution error from the other is not saved.

	This PR includes the following changes:

	* Do not display select(2) as the system call that caused the raised error, as it is for internal processing

	* Fix bug: Get errno with Socket::SO_ERROR in Windows environment with a workaround for tests not passing

Since it's a singleton method, it should be referenced as `Socket.tcp_fast_fallback=`,
not `Socket#tcp_fast_fallback=`.

This change includes the following updates:
- Added an environment variable `RUBY_TCP_NO_FAST_FALLBACK` to control enabling/disabling fast_fallback
- Updated documentation and man pages
- Revised the implementation of Socket.tcp_fast_fallback= and Socket.tcp_fast_fallback, which previously performed dynamic name resolution of constants and variables. As a result, the following performance improvements were achieved:

(Case of 1000 executions of `TCPSocket.new` to the local host)

Rehearsal -----------------------------------------
before   0.031462   0.147946   0.179408 (  0.249279)
after    0.031164   0.146839   0.178003 (  0.346935)
-------------------------------- total: 0.178003sec

            user     system      total        real
before   0.027584   0.138712   0.166296 (  0.233356)
after    0.025953   0.127608   0.153561 (  0.237971)

The following two commits fix the proper clearing of the Connection Attempt Delay in `TCPSocket.new`.

- https://github.com/ruby/ruby/pull/12087/commits/b2f610b0edf8f84d9d0fce038f3ebfa9f2cb0223
- https://github.com/ruby/ruby/pull/12223/commits/6f4efaec5352cdeb6cab86036a83f53c9fa5c3d2

The same fix will be applied to `Socket.tcp`.

With the introduction of Happy Eyeballs Version 2 to `Socket::tcp`, the following areas have been mainly enhanced:

- How the value specified for `connect_timeout` works
- How Socket.tcp operates with Happy Eyeballs Version 2

A description for the new option `fast_fallback` has been added in https://github.com/ruby/ruby/pull/11813.