Use better data type info in decoders

Use better data type info in decoders

The decoders in some cases failed to capture or propagate
information about what is being decoded, causing more work
happen to try unrelated decoders as a fallback.

We now try harder to keep track of the expected object (private key or
public key, if known), and the algorithm determined from the OID of a
PKCS8 object or SPKI.  This leads in many cases to fewer decoder
invocations.  With so many more algorithms now, trying every decoder
is increasingly best avoided.

Reviewed-by: Dmitry Belyavskiy <beldmit@gmail.com>
Reviewed-by: Tim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/26892)