am 19a4bd1: AI 147710: Add redirects for sdk/preview pages.

Merge commit '19a4bd164eec255f62cde30f4afc39f0aeb35c04' into donut

* commit '19a4bd164eec255f62cde30f4afc39f0aeb35c04':
  AI 147710: Add redirects for sdk/preview pages.
tree: 7a37fcb70d072f4e7b6234b9be4a14103450d0f8
  1. core/
  2. libs/
  3. target/
  4. tools/
  5. buildspec.mk.default
  6. cleanspec.mk
  7. envsetup.sh