isl/tests: Use a longer path for isl.h

The tests assumed that isl would be in the include path but that usually
isn't the case.  Instead, we usually have src/intel and you need to add an
"isl/" prefix.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Matt Turner <mattst88@gmail.com>
1 file changed