In order to unblock CL 244057 (which fixes #39945), we need to rebuild the android-amd64-emu builder image given that CL 247357 has been submitted.
Doing so needs some fixes because a (Debian) package became unavailable due to a security issue. Copied from a CL comment:
I tried building the new image, but ran into problems.
The openjdk-8-jdk package is no longer available in debian buster (search results suggest because of a security problem). I tried using openjdk-11-jdk instead, but then one of the sdkmanager invocations ran into a java.lang.NoClassDefFoundError exception. Maybe we should update to a newer Android SDK.