Executable page non W3C compliant if there are no files

[vmcj]

Description of the problem

The W3C test fails if there is an Executable without any run/build files

Your environment

Main

Steps to reproduce

Create a language in the defaultdata language fixture
Don't add the run/build files in the sql/files/defaultdata

Expected behaviour

This is a very small edge case but we should be compliant

Actual behaviour

Test fails,

Any other information that you want to share?

I'm creating this issue mostly to remember to fix this, this should be a small thing to fix.