Add WebKitPrivateFrameworkStubs for iOS 11

Add WebKitPrivateFrameworkStubs for iOS 11
https://bugs.webkit.org/show_bug.cgi?id=173988

Reviewed by David Kilzer.

Source/JavaScriptCore:

* Configurations/Base.xcconfig: iphoneos and iphonesimulator should use the
same directory for private framework stubs.

Source/WebCore:

* Configurations/WebCore.xcconfig: iphoneos and iphonesimulator should use the
same directory for private framework stubs.

Source/WebCore/PAL:

* Configurations/PAL.xcconfig: iphoneos and iphonesimulator should use the
same directory for private framework stubs.

Source/WebKit/mac:

* Configurations/WebKitLegacy.xcconfig: iphoneos and iphonesimulator should
use the same directory for private framework stubs.

Source/WebKit2:

* Configurations/BaseTarget.xcconfig: iphoneos and iphonesimulator should use the
same directory for private framework stubs.

Tools:

* DumpRenderTree/mac/Configurations/Base.xcconfig: iphoneos and iphonesimulator
should use the same directory for private framework stubs.
* WebKitTestRunner/Configurations/Base.xcconfig: Ditto.

WebKitLibraries:

* WebKitPrivateFrameworkStubs/iOS/9: Add Mac architecture for Simulator.
* WebKitPrivateFrameworkStubs/iOS/10: Ditto..
* WebKitPrivateFrameworkStubs/iOS/11: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@219140 268f45cc-cd09-0410-ab3c-d52691b4dbfc