Reenabling the disabled DestroyInSysCommandNCLButtonDownOnCaption and SysCommandMoveOnNCLButtonDown…

Reenabling the disabled DestroyInSysCommandNCLButtonDownOnCaption and SysCommandMoveOnNCLButtonDownOnCaptionAndMoveTest tests

I was able to get these tests to fail if the mouse was anywhere in the vicinity of the window. The tests were calling the
SetCursorPos API to avoid this. I guess it could happen if other tests on the bot via the shard end up moving the
cursor.

The fix is to peek out the messages pending in the queue after the window is visible. Generally Windows posts a WM_MOUSEMOVE
message when a window becomes visible to allow it to set the cursor. Perhaps this is what is tripping us up.
Removed the SetCursorPos call.

BUG=592742

[ananta, 2016-03-12 03:35:52]

ananta@chromium.org changed reviewers:
+ sky@chromium.org

[sky, 2016-03-14 15:03:51]

On 2016/03/12 03:35:52, ananta wrote:

Seems better to move these to interactive ui tests so you know the test is run
without any other tests running at the same time.