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)

crypto/thread/build.info

@@ -14,7 +14,7 @@ ELSE
   IF[{- !$disabled{quic} -}]
     SOURCE[../../libssl]=$THREADS_ARCH
   ENDIF
-  $THREADS=api.c
+  $THREADS=api.c arch/thread_win.c
 ENDIF
 
 SOURCE[../../libcrypto]=$THREADS