Fix dev branch CircleCI

[egpast]

Currently, all dev branch publish_docs jobs are failing the Java 11 requirement.

A lot of things need to be changed to pass that requirement:

• Install OpenJDK 11 instead of 8
• Install new Android command-line tools. The old SDK tools don't support JDK 8. Oddly, the new tools don't install to the right location, so they need to be moved around a little before they'll work.
• Install Python 3.9.4 (required by Ant)
• Build Buck! Release-branch builds require Java 8, so we can't use those and hope to pass the version check.
• Pass down our local Buck executable to docs/publish.sh and docs/soyweb-prod.sh. Otherwise, these scripts will try to use the Ant-bootstrapped Java 8 Buck instead of our locally built Java 11 Buck. They'll still use buck by default, so local usage is unaffected.

This has been tested by adding a couple tweaks in a separate branch to force publish_docs to run on commits and stop it from actually publishing, and then confirming that CircleCI passes.