Roll isolate binaries generated at infra@c4b32da

Isolate sha1s were taken from the following builds:

https://luci-milo.appspot.com/buildbot/chromium.infra/infra-continuous-precise-64/10415
https://luci-milo.appspot.com/buildbot/chromium.infra/infra-continuous-mac-10.10-64/9839
https://luci-milo.appspot.com/buildbot/chromium.infra/infra-continuous-win-64/10696

This will pick up an isolate binary which the following changes:

* exparchive subcommand is removed,
* archive and batcharchive now ignore --exparchive (treating it as true). The
  old implementations for archive and batcharchive (i.e. those used
  when --exparchive=false) no longer exist.
* --max-concurrent-uploads defaults to 8.

Submitting this CL will have the effect of rolling out the exparchive-based
implementations everywhere.

Bug: 692940
Change-Id: I01b57c4b00ec8f82c2b1c162782da497d40bb55c
Reviewed-on: https://chromium-review.googlesource.com/835769
Commit-Queue: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Michael McGreevy <mcgreevy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#525352}

tools/luci-go/linux64/isolate.sha1

-0c5f61171e70fabea55489eccb330687e94a43a3
+3edf192dfe8e2b9c5e89e3885b7bb27bac3450f0

tools/luci-go/mac64/isolate.sha1

-f79355e863ef6e67a074ed85b043db81376ffbde
+869b8c39e30c2b19fa82be5eb4642f29720ba634

tools/luci-go/win64/isolate.exe.sha1

-a7682ca46f9ac393f3e8c3b8feb4aa7cef49693f
+dd9791d5ac0e667a17ded140c3bf0bf9673b0da5