Enable VIDEO_PRESENTATION_MODE only in Debug and Release builds on Mac

Enable VIDEO_PRESENTATION_MODE only in Debug and Release builds on Mac
https://bugs.webkit.org/show_bug.cgi?id=153665

Reviewed by Dan Bernstein.

Source/JavaScriptCore:

* Configurations/FeatureDefines.xcconfig:

Source/WebCore:

* Configurations/FeatureDefines.xcconfig:

Source/WebKit/mac:

* Configurations/FeatureDefines.xcconfig:

Source/WebKit2:

* Configurations/FeatureDefines.xcconfig:

Source/WTF:

* wtf/Platform.h:
Remove this as the flag is already defined in FeatureDefines.xcconfig files.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@195901 268f45cc-cd09-0410-ab3c-d52691b4dbfc