Move Windows try slaves to Windows XP.
Move Windows try slaves to Windows XP.

TBR=nsylvain
TEST=none
BUG=none

Review URL: http://codereview.chromium.org/4112002

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@63850 0039d316-1c4b-4281-b951-d872f2087c98

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