Microptimize gives_check() for castling case

Without patch we have 333198 nps, with patch 334249.

A very small +0.3%, not a lot manily becuase this is a
side path that is taken very few times.

Anyhow idea is correct becuase first 'quick' condition
has an hit rate of about 95%.

No functional change.
Merge remote-tracking branch 'upstream/master'