[Windows] Update various build tools to understand VS2010 environment.
https://bugs.webkit.org/show_bug.cgi?id=116169.

Reviewed by Anders Carlsson.

* Scripts/build-api-tests: Identify VS2010 environment.
* Scripts/build-dumprendertree: Ditto.
* Scripts/build-webkit: Ditto.
* Scripts/webkitdirs.pm:
(dieIfWindowsPlatformSDKNotInstalled): Update to recognize a wider
range of acceptable SDK's.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@150131 268f45cc-cd09-0410-ab3c-d52691b4dbfc