GetPropertyAtIndexAsArgs returns true on success and false on failure. Right
now it returns the converted size_t returned from GetArgs which describes
the number of arguments in the argument list. So for empty argument lists
((size_t)0 -> (bool)false) this function always fails.
The only observable effect of this seems to be that empty arguments are never
propagated to the internal LaunchInfo for a process. This causes that once any
argument has been added to target.run-args, clearing target.run-args doesn't
have any effect.
Fixes issue #55568