cc Minor housekeeping.
Remove some duplication in test names.
Fixing CR AT EOL errors
[çc] Add conformance-checker tests for <picture>
Remove .DS_Store
Test 1x and 1.0x
Add lint for common testharness.js mistakes and clean up tests that make those mistakes.
Add some srcset/sizes tests with empty value, single comma, multiple commas
Fix review comments
Add some tests for missing srcset on source
Fix review comments
Add a test with /**/ in srcset
Fix trailing css comment test
Fix aria region test name
Ban role=presentation
Merge pull request #1043 from zcorpan/cc-picture

[çc] Add conformance-checker tests for <picture>
[cc] Make some ITS-in-HTML tests conformant.