Merge change 21778 into donut

* changes:
  CTS: Enable Python description/plan generator
tree: 1960537443613edd72a84143819dd16b23505d62
  1. core/
  2. libs/
  3. target/
  4. tools/
  5. buildspec.mk.default
  6. cleanspec.mk
  7. envsetup.sh