Add test stage with minified Android builds

[rorbech]

This adds a test-sync test stage running all sync tests with minification on Android. It was not possible to add minification for test-base due to our current project setup, but as test-sync holds quite many models and cover reasonably base functionality it will in fact act as a sanity validation of our library-base/proguard-rules-consumer-common.pro configuration, especially initialization of the native class and method references.

If needed it is relatively easy to manually run the full test-base test suite with minification following the instructions in test-base/build.gradle.kts

Closes #1114

[clementetb]

We could enable running test-base with minification in CI if we remove its dependency from test-sync. We could manually link the shared sources and add the kotlinx-datetime dependency to test-sync.

[cmelchior]

If CI is green