Set CHROME_BIN on DDC bot
Set CHROME_BIN on DDC bot

Noticed the Linux bot is failing on this:

https://build.chromium.org/p/client.dart.fyi/builders/ddc-linux-release-be/builds/1724/steps/ddc%20tests/logs/stdio

R=whesse@google.com

Review-Url: https://codereview.chromium.org/2640093002 .

dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dartino/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dartino/dart-sdk,dart-archive/dart-sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk,dartino/dart-sdk,dart-lang/sdk,dart-archive/dart-sdk,dart-lang/sdk,dart-lang/sdk,dart-archive/dart-sdk