Roll Syzygy deps.

Version 0.8.0.0

As of this version, SyzyASan has been entirely refactored and much of it
reimplemented. New mechanisms exist for finding bugs in external/uninstrumented
code, and coverage has been increased.

This version also marks the official separation of Syzygy from Sawbuck, it's
original ancestor. Syzygy is now hosted in a pure GIT repository, and built with
Ninja.

Some highlights:

[4e6b4f9b19] Refactor of zap_timestamp.
[a01d2374e6] SyzyASan - Zebra heap fully implemented.
[990009f460] SyzyASan - Large block heap fully implemented.
[735e51eb5c] SyzyASan - Narrowed crash race conditions as much as possible.
[08ebb870d9] Full Ninja support for the build.
[45d2fb0bec] SyzyASan - CTMalloc support added.
[217fe21486] Fully split from Sawbuck repository.

BUG=

Review URL: https://codereview.chromium.org/640813007

Cr-Commit-Position: refs/heads/master@{#300996}

DEPS

@@ -729,7 +729,7 @@ hooks = [
     'action': ['python',
                'src/build/get_syzygy_binaries.py',
                '--output-dir=src/third_party/syzygy/binaries',
-               '--revision=363bc02a09c380b6f5f397606cc0744d85d54a51',
+               '--revision=6a46c83649012c692b940218a4a2a8f560d4df77',
                '--overwrite',
     ],
   },