Merge stable-3.2 into stable-3.3

* stable-3.2:
  Remove standalone build mode
  Upgrade bazlets to latest stable-3.2 to build with 3.2.5.1 API
  Upgrade bazlets to latest stable-3.1 to build with 3.1.10 API
  Bump Bazel version to 3.7.0
  Upgrade bazlets to latest stable-3.0 to build with 3.0.13 API
  Bump Bazel version to 3.5.0

Change-Id: Ie48eaa92fe8fb57877e3da7aed24df0a4cc15fed