target/sh4: Unify code for CHECK_NOT_DELAY_SLOT

We do not need to emit N copies of raising an exception.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Message-Id: <20170718200255.31647-19-rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
