Add test for EVP_KEYMGMT leak in evp_pkey_signature_init() error paths

Add test for EVP_KEYMGMT leak in evp_pkey_signature_init() error paths

Verify that calling EVP_PKEY_sign_init_ex2() with a mismatched
key/signature algorithm (RSA key with ECDSA signature) does not leak
EVP_KEYMGMT references. The test repeats the operation 100 times so
that ASAN can detect accumulating leaks.

Reviewed-by: Shane Lontis <shane.lontis@oracle.com>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
Reviewed-by: Eugene Syromiatnikov <esyr@openssl.org>
MergeDate: Fri Feb 13 14:42:40 2026
(Merged from https://github.com/openssl/openssl/pull/29810)