Do not suspend CSS animations when page is hidden

Do not suspend CSS animations when page is hidden

[Title] Do not suspend CSS animations when page is hidden
[Issue#] TDIS-5549
[Problem] CSS animation gets suspended when moved to background.
[Cause] commit f9d52256dc1509696c042ae7b7400fbaa271e8bd
        was added to save CPU resource when page is hidden.
        However, animated attributes are changed without it being
        painted when page is in background, so almost no CPU resources
        are used when css animation runs on a page that is hidden.
[Solution] revert previous patch

Change-Id: Idf54192a75709c2a6db1f755e9fb233b58eb2185