Run unit tests in Android CI pipeline

[Copilot]

Resolves #912 by implementing a new Android testing approach that eliminates the Gradle dependency and introduces a new emulator-based testing system that builds and executes individual test executables directly in the Android emulator via ADB. This is achieved by a new custom shell script run-android-tests.sh and an updated CI pipeline to install the required Android emulator image. Additionally, required testdata scattered across the repo (/sf2, /test) are now staged in a dedicated test-directory, allowing them to be easily picked up and pushed over to the Android emulator.

Benefits

• ✅ No Gradle dependency: Pure CMake + ADB approach
• ✅ Individual test files: Each test remains in its own C source file
• ✅ Better debugging: Individual test failures are isolated and easier to troubleshoot
• ✅ Maintainable: No function name mangling or test merging required

Caveats

• Unit tests are not executed on ARM and AARCH64 architectures, as this would require expensive software emulation, which takes hours to even only boot the emulator image...
• The legacy unmaintained Gradle-based approach has been removed.

Co-Authored by Claude Sonnet 4.6 and Qwen 3.8.

[derselbst]

Current status: Rebased against recent master. Got the android emulator up and running. Unit tests are running as well on x86. Disabled tests to run on arm and aarch64, as it's not supported by qemu2. Tests requiring test data are currently still failing. TODOs: Fix those tests. And stop duplicating the list of unit tests using the ADD_FLUID_ANDROID_TEST cmake command.

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud