[Isolate] Update clients to hit /_ah/api instead of /api
[Isolate] Update clients to hit /_ah/api instead of /api

The webapp2 adapter is now serving at /_ah/api, the old Endpoints v1 path.

https://chromium.googlesource.com/infra/infra revision:
d8ec646a9503426a5018cf5bc251abe4a842357f

https://chromium.googlesource.com/infra/luci/luci-go revision:
928030a644473add1ca1bd044d13f48fee569c1a

Build:
https://ci.chromium.org/buildbot/chromium.infra/infra-continuous-trusty-64/12546

Bug: skia:8055
Change-Id: I352ab8b0dd76d699b2698a80424e69a14b21f334
Reviewed-on: https://skia-review.googlesource.com/132700
Commit-Queue: Eric Boren <0e499112533c8544f0505ea0d08394fb5ad7d8fa@google.com>
Auto-Submit: smut <95deb7aa15d4c615299e47e7688551456568b1fb@google.com>
Reviewed-by: Eric Boren <0e499112533c8544f0505ea0d08394fb5ad7d8fa@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot