BUGZILLA-1111383 Don't assume that 'kind' is a valid key

'kind' is not necessarily emitted during a declDef record creation,
so we should provide a default value of None to avoid crashing.

https://bugzilla.mozilla.org/show_bug.cgi?id=1111383
Sure, tests are always good! But I can see this fixes a bug by examination, and I just so happen to be trying to get through a big indexing run myself at the moment, so I'm not going to be a stickler. :-) Let's remove the Nones from the others. People used to Python won't need the extra explicitness to remind them.