Update isolate binary.

https://crrev.com/c/881949 Making tarring isolate deterministic.

R=maruel

Bug: 804869
Change-Id: I3d4582eb9aa55aa764778b48027081e1d106d310
Reviewed-on: https://chromium-review.googlesource.com/898524Reviewed-by: Vadim Shtayura <vadimsh@chromium.org>
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533925}

tools/luci-go/README.md

 # luci-go
 
 Contains executable built out of
-https://github.com/luci/luci-go/tree/master/client/cmd/.
+https://chromium.googlesource.com/infra/luci/luci-go/+/master/client/cmd
 
 The binaries are retrieved from the following builders:
 

tools/luci-go/linux64/isolate.sha1

-3edf192dfe8e2b9c5e89e3885b7bb27bac3450f0
+b1c3c39fe8fe084bd2ec4ed0f03037751a3a8650

tools/luci-go/mac64/isolate.sha1

-869b8c39e30c2b19fa82be5eb4642f29720ba634
+ffb6a624bd14abdff34618fe97562b34350199f7

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

-dd9791d5ac0e667a17ded140c3bf0bf9673b0da5
+bb2a587cbc0a8e5b0ae41be4ffb5ad33b213dcf9