Sanitizer spring cleaning

  - Build ASAN and TSAN with skia_gpu=0.
  - Update tags to Ubuntu13.10-GCE-NoGPU for ASAN and TSAN bots.
  - Switch TSAN to Release mode.  It'll work better that way.
  - Remove Valgrind, ASAN, and TSAN builders.  They're runtime tools, so
    just building them won't tell us anything beyond a normal build,
    especially for Valgrind which doesn't build differently at all.

BUG=skia:2640
R=borenet@google.com, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/311233003