Merge dev15.7 to dev15.8

[dotnet-bot]

This is an automatically generated pull request from dev15.7 into dev15.8.

git fetch --all
git checkout merges/dev15.7-to-dev15.8
git reset --hard upstream/dev15.8
git merge upstream/dev15.7
# Fix merge conflicts
git commit
git push merges/dev15.7-to-dev15.8 --force

Once all conflicts are resolved and all the tests pass, you are free to merge the pull request.