sha/asm/sha1-x86_64.pl: fix crash in SHAEXT code on Windows.
sha/asm/sha1-x86_64.pl: fix crash in SHAEXT code on Windows.

RT#4530

Reviewed-by: Tim Hudson <eb0be8e447f673b41b10eda09d63cd72526b0a42@openssl.org>

openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl