Fix error handling in CRYPTO_get_ex_new_index

Fix error handling in CRYPTO_get_ex_new_index

If an out of memory error happens when the index zero
is reserved in a newly created ip->meth stack object,
that reservation is not done in a second attempt, which makes
various X_set_ex_data overwrite the value of X_set_app_data.

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/22149)

(cherry picked from commit d4f22a915ac50570015a23ad794032c4fb9496cb)