insane.bbclass: Add test for shebang line length

Shebang lines longer than 128 characters can give an error
depending on the operating system.
This implements a test that signals an error when locating a
faulty shebang.

YOCTO: #11053

Signed-off-by: Domarys Correa <domarys.correa@ossystems.com.br>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>