Switch windows build to Visual Studio 2017

Switch windows build to Visual Studio 2017
https://bugs.webkit.org/show_bug.cgi?id=172412

Patch by Stephan Szabo <stephan.szabo@sony.com> on 2017-12-05
Reviewed by Per Arne Vollan.

.:

* Source/cmake/OptionsMSVC.cmake:

Source/JavaScriptCore:

* JavaScriptCore.vcxproj/JavaScriptCore.proj:

Source/WebCore:

Only changes proj file to update generator

* WebCore.vcxproj/WebCore.proj:

Source/WebKitLegacy:

* WebKitLegacy.vcxproj/WebKitLegacy.proj:

Source/WTF:

* WTF.vcxproj/WTF.proj:
* wtf/Compiler.h:

Tools:

* Scripts/build-webkit:
* Scripts/webkitdirs.pm:
(visualStudioInstallDir):
(visualStudioInstallDirFallback):
(msBuildInstallDir):
(setupAppleWinEnv):
(setupCygwinEnv):
(generateBuildSystemFromCMakeProject):
(pickLegacyVisualStudioInstallation): Deleted.
(visualStudioInstallDirLegacy): Deleted.
(visualStudioVersion): Deleted.
(visualStudioVersionFromInstallDir): Deleted.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@225563 268f45cc-cd09-0410-ab3c-d52691b4dbfc