Revert "always optimize third_party code"

This reverts commit c766370d86cdf73b5edcc1e67c32316345ca89d7.

Reason for revert: speculative -- trying to fix Debian breaks (pdf?)

Original change's description:
> always optimize third_party code
> 
> Change-Id: I5b2244460a4760e9336640f597d0f74c374a0d04
> Reviewed-on: https://skia-review.googlesource.com/155641
> Commit-Queue: Mike Klein <mtklein@google.com>
> Commit-Queue: Brian Osman <brianosman@google.com>
> Auto-Submit: Mike Klein <mtklein@google.com>
> Reviewed-by: Brian Osman <brianosman@google.com>

TBR=mtklein@google.com,brianosman@google.com

Change-Id: I5467c95f9487c31e6f538f13579e490cdaeeee2e
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/155607
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
3 files changed