"test_close_after_socket_close" checks if ssl.close is no-op even after
the wrapped socket is closed. The test itself is fair, but the other
endpoint that is reading the SSL connection may fail with SSLError:
"SSL_read: unexpected eof while reading" in some environments:
https://github.com/ruby/ruby/actions/runs/60085389 (MinGW)
https://rubyci.org/logs/rubyci.s3.amazonaws.com/android28-x86_64/ruby-master/log/20200321T034442Z.fail.html.gz
```
1) Failure:
OpenSSL::TestSSL#test_close_after_socket_close [D:/a/ruby/ruby/src/test/openssl/utils.rb:299]:
exceptions on 1 threads:
SSL_read: unexpected eof while reading
```
This changeset rescues and ignores the SSLError in the test.