Further improve/fix ec_GFp_simple_points_make_affine (ecp_smpl.c) and
group_order_tests (ectest.c).  Also fix the EC_POINTs_mul documentation (ec.h).

Reviewed-by: emilia@openssl.org

Conflicts:
	crypto/ec/ectest.c

Conflicts:
	crypto/ec/ec.h
Fixed out-of-bounds read errors in ssl3_get_key_exchange.

PR#3450

Conflicts:
	ssl/s3_clnt.c

Reviewed-by: Emilia Käsper <emilia@openssl.org>