Fix no-thread-pool build on Windows

thread/arch/thread_win.c must be included into libcrypto as rcu depends
on ossl_crypto_mutex implementation on Windows.

Fixes #25337

Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Tom Cosgrove <tom.cosgrove@arm.com>
Reviewed-by: Hugo Landau <hlandau@devever.net>
(Merged from https://github.com/openssl/openssl/pull/25378)

(cherry picked from commit f0fd24d5)