Include kotlin test apps in artifacts
Include kotlin test apps in artifacts

Kotlin files in java sources does not show up java sources which means
we don't copy test apks into dist. This CL fixes it by checking for
kotlin files in java source dirs manually.

Since the apk does not have any code, i needed to create a dummy class
so that the build script copies its APK to the dist folder.

Test: local build
Bug: 68020016
Change-Id: I940527e0fe4a91a9c9432eec6b1f759f47feeb5b

AndroidX/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,AndroidX/androidx,androidx/androidx,aosp-mirror/platform_frameworks_support,androidx/androidx,AndroidX/androidx,aosp-mirror/platform_frameworks_support,androidx/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,aosp-mirror/platform_frameworks_support,aosp-mirror/platform_frameworks_support,AndroidX/androidx,AndroidX/androidx,androidx/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,AndroidX/androidx,androidx/androidx,aosp-mirror/platform_frameworks_support