client.skia: Add duplicate slaves for Win8 i7-4790k and GTX960
client.skia: Add duplicate slaves for Win8 i7-4790k and GTX960

BUG=skia:3922

Review URL: https://codereview.chromium.org/1208203002

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@295853 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build