isolate: wrap some error
isolate: wrap some error

Bug: 1217912
Change-Id: I07be276d50f4d6ccfa4740020f93eb6e2e548e06
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/2948229
Auto-Submit: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Commit-Queue: Yoshisato Yanagisawa <5d95c5c75e3d691d9c77888fff4498e04f8b7157@google.com>
Reviewed-by: Yoshisato Yanagisawa <5d95c5c75e3d691d9c77888fff4498e04f8b7157@google.com>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go