Fix internal Windows build of projects built after WebKit

Fix internal Windows build of projects built after WebKit
https://bugs.webkit.org/show_bug.cgi?id=154249
rdar://problem/24644805

Reviewed by Chris Dumez.

Source/WebKit:

* PlatformWin.cmake:
Copy all generated headers to ForwardingHeaders/WebKit, not just WebKit.h.
This should fix problems related to not finding headers from other projects, such as AccessibleApplication.h.
WebKit.h, WebKitCOMAPI.h, and CFDictionaryPropertyBag.h were copied correctly, so this should copy the rest
of the needed headers.

Tools:

* DumpRenderTree/PlatformWin.cmake:
* MiniBrowser/win/CMakeLists.txt:
Don't include DerivedSources/WebKit/Interfaces to make MiniBrowser and DumpRenderTree
more like projects built internally after WebKit.  They should only need to use what
is in ForwardingHeaders/WebKit.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@196589 268f45cc-cd09-0410-ab3c-d52691b4dbfc