Fix/ssl shutdown

[bcardiff]

Fix #7364

After #7068 the logic to ignore the OpenSSL::SSL::Error::SYSCALL while closing the connection was lost.

This PR also removes unused code for when Errno was raised.

It adds some manual specs that exhibited issues: request to google and closing the connection before consuming the body. These are domain sensible.

[bcardiff]

FYI the other manual specs includes badssl_spec.cr, but it's been a long time since they were added but there were not checked regularly. I've found that connecting to incomplete-chain.badssl.com hangs and the last it fails with

       Closed stream (IO::Error)
         from src/io.cr:128:5 in 'check_open'
         from src/io/buffered.cr:116:5 in 'write'
         from src/openssl/bio.cr:24:7 in '->'
         from BIO_write
         from ssl3_write_pending
         from do_ssl3_write
         from ssl3_write_bytes
         from ssl3_write
         from SSL_write
         from src/openssl/ssl/socket.cr:121:5 in 'unbuffered_write'
         from src/io/buffered.cr:205:5 in 'flush'
         from src/io/buffered.cr:213:5 in 'close'
         from spec/manual/badssl_spec.cr:13:3 in 'connect_to'

cc: @jhass

[bcardiff]

I think we can add a make manual_spec target to run this slow specs and we can include them in nightly build or at least in test-ecosystem.