The logic to do or not the validation of TBD against IR was incorrect.
In the case of modules, the comment described what was supposed to
happen (skipping the validation if the module had SIB files), but the
code was returning if the module had or not SIB files, which would have
returned true for any module without SIB files without checking if the
compiler was build in a debug configuration or not.
This was only visible in the case of non-debug builds, and it only
appeared for us in a convoluted mix of optimized builds with
-enable-testing on some modules.
