If the default is not set for a lazy loaded option,
canonical parser output key ends up being 'lazy_option=default',
because when computing the keys we exclude defaults.
If on the other hand we register a default for a lazy option,
it does not get loaded, since in lazyLoadOption we believe
the default is already the loaded value.
Change-Id: I92b3e18fabef4eecac2ec2a4844f1be2716e5d89
Needed-By: I3bce04684070ad306685dabbc51267def25773cd
79475042a5