Avoid another copy of key schedule pointer in PROV_GCM_CTX

Avoid another copy of key schedule pointer in PROV_GCM_CTX

This copy would need an update on dupctx but
rather than doing it just remove the copy.

This fixes failures of evp_test on Windows with
new CPUs.

Reviewed-by: Todd Short <todd.short@me.com>
Reviewed-by: Hugo Landau <hlandau@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22384)