Be more selective about copying libcrypto symbols into legacy.so

Be more selective about copying libcrypto symbols into legacy.so

Some private libcrypto symbols are also included in legacy.so.
Unfortunately this included some files with "RUN_ONCE" functions and
global data. This doesn't get properly cleaned up when OpenSSL exits.
Therefore we are more selective about the symbols we include in legacy.so.

Fixes #13560

Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14646)