Autobuild ignores default build variant setting for Android projects

CodeQL autobuild apparently always tries to build the alphabetically earliest build variant for an Android project, ignoring alternate default build variant settings specified in `build.gradle`:

- https://issuetracker.google.com/issues/36988145
- https://stackoverflow.com/questions/52072162/how-to-change-android-studios-default-build-flavor

For example, my project [SMS Import / Export](https://github.com/tmo1/sms-ie) has four build variants, and the default is set to `standardDebug`. Android Studio respects this, but CodeQL autobuild still tries to build `legacyDebug`.

首先跟踪 CodeQL 对 Android autobuild 的处理方式，以及它如何根据项目的 build.gradle 确定构建变体。使用链接的 SMS Import / Export 项目重现该问题：该项目将 standardDebug 定义为默认变体，而 autobuild 选择了 legacyDebug。当 autobuild 遵循已配置的默认变体时，即视为完成。

由索引模型根据 Issue 内容生成。