nodom: workerDOM should be document.defaultView

[samouri]

summary
Fixes ampproject/amphtml#35902

1. Renames DocumentLite.ts to DocumentStub.ts. The filename should match the exported class :)
2. Modifies workerDOM export to actually be the document.defaultView which is essential for propagating properties (localStorage/sessionStorate) to the global self. This is also how the regular binary works. See below snippets

worker-dom/src/main-thread/worker.ts

Line 80 in 11ff429

Object.keys(workerDOM).forEach(function(k){self[k]=workerDOM[k]});

worker-dom/src/worker-thread/index.amp.ts

Line 137 in 11ff429

return document.defaultView;

testing done
Copied the built binaries over to a local amphtml and confirmed that localStorage access was available on self

[rcebulko]

worker-dom/src/main-thread/worker.ts

Line 80 in 11ff429

Object.keys(workerDOM).forEach(function(k){self[k]=workerDOM[k]});

Why can't this be Object.assign(self, workerDOM);?

[samouri]

worker-dom/src/main-thread/worker.ts

Line 80 in 11ff429

Object.keys(workerDOM).forEach(function(k){self[k]=workerDOM[k]});

Why can't this be Object.assign(self, workerDOM);?

Probably can be! Feel free to make a separate PR!