The difference between this PR and the original is the change to the `AndroidManifest.xml`. For context, right before the original PR landed, [a change to upgrade the target sdk](https://github.com/flutter/engine/pull/47683) in the manifest from 31 to 33 landed. It also removed the lint complaining about using an old target sdk version from the baseline lint file. So this change upgrading the sdk, but not the target sdk in the manifest, triggered the lint again.
For the rest of the PR, [see the description of the original PR](https://github.com/flutter/engine/pull/47609).
[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
Reverts flutter/engine#47609
Initiated by: zanderso
This change reverts the following previous change:
Original Description:
~**This should not land until https://github.com/flutter/buildroot/pull/790 (re)lands, and I swap the buildroot url back to the latest commit.**~ ~Reland of PR to update buildroot at https://github.com/flutter/buildroot/pull/792. ~ <- landed, and changed the buildroot commit to the latest in DEPS
Upgrades to android api 34
Also:
1. Upgrades to java 17 in DEPS/ci, because the linter now requires it.
2. Stops running some roboelectric tests on android apis 16-18, because Roboelectric indicated those versions were unsupported and we don't support them either.
3. Applies the four trivial new suggestions from the newer linter.
4. Updates the baseline lint to include the new non-trivial lint ([fixed in a different PR](https://github.com/flutter/engine/pull/47817/files)).
5. Changes some instances where we were hardcoding android apis as numbers (e.g. `sdk = 16') to use version codes (see the [comment below](https://github.com/flutter/engine/pull/47609#issuecomment-1800308658)).
[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
* Reland "Use a Pbuffer surface when the onscreen surface is not available for snapshotting on Android (#27141)" (#27607)"
This reverts commit 78663924741a29aeca10648015e39db6fbd28be4.
* Do not let gradle download SDK deps
