Automatically verify that XML/Intellisense docs are included in SDK output

[crummel]

Should be easily automatable and eliminates a manual step in servicing validation.

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[omajid]

I have a test script that I used in #1686

[omajid]

A couple of questions:

• My original test (as mentioned in the comment above) as in bash. Is that suitable for inclusion in source-build? Or should I try and re-write it in something more cross-platform?
• Should this be plugged into smoke-test.sh or is there a better place for this test?

[omajid]

Now that #2137 is merged, is it okay to close this issue now?