Remove Nexus9 bots

BUG=skia:

Change-Id: I65705a6142a96a476c2d9eae79aeaaa29ade2dde
Reviewed-on: https://skia-review.googlesource.com/5928
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
2 files changed
tree: abfc75707dab1da18844fe9db0240654bedad050
  1. recipe_modules/
  2. recipes.py
  3. recipes/