Code health: Removed the use of ComPtr::GetAddressOf in Win unit tests

The use of ComPtr::GetAddressOf is banned see
http://crbug.com/914910
Either the "&" operator or the ReleaseAndGetAddressOf method should be used.
Also, the "CopyTo" method could be replaced with the "As" method which is easier to type and call.

R=aleventhal@chromium.org, kbabbitt@microsoft.com

RelNotes: N/A
Bug: 914910
Change-Id: I4fda494dfe9d51247bd7e82c9ec80b3e5ad5813f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2120093
Commit-Queue: Nektarios Paisios <nektar@chromium.org>
Reviewed-by: Kevin Babbitt <kbabbitt@microsoft.com>
Reviewed-by: Aaron Leventhal <aleventhal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#753328}