client: do not use isolated in win7
client: do not use isolated in win7

64bit bots have the same issue.
https://chromium-swarm.appspot.com/task?id=4a08f76ca035d110

Bug: 932396, 1045281
Change-Id: I0d57e1bbffbfa54f6702d6facb480f8dd7a407a0
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-py/+/2027347
Auto-Submit: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Commit-Queue: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>
Reviewed-by: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>

luci/luci-py,luci/luci-py,luci/luci-py,luci/luci-py