Following bug 1774454, the JS getters on internal module objects are only used by test code, via the shell module object wrapper system. None of these objects are exposed to JS.

If change the shell module object wrappers to use the C++ accessors we can remove these getters entirely.

Test code interacts with these module objects by means of the shell object
wrappers. If we add a few more C++ accessors where necessary we can use these
instead of calling the JS property getters.

Since these getters are now unused we can remove them.

Depends on D151133

Since these no longer have any methods or getters we can give them null prototypes.

Depends on D151134

https://hg.mozilla.org/mozilla-central/rev/071ec66b1874
https://hg.mozilla.org/mozilla-central/rev/f2acb176f0ff
https://hg.mozilla.org/mozilla-central/rev/4381d9d2dce1