Run Android Junit

Using this project as a base to understand how to run JUnit Android test within the shared Library: https://github.com/Kotlin/kmm-sample/blob/master/shared/src/androidTest/kotlin/com/jetbrains/kmm/shared/androidTest.kt

Cross-posting from Android Studio issue: https://issuetracker.google.com/issues/191287536
I'm not sure if it's a code issue (so a modification on this code base), or a IDE issue.

**Goal:** run with JUnit the tests with the Android configuration on the shared module.

**Issue:** the junit test folder is not recognized as such with Android, it seems to be override by an Android Connected test.

**Symptoms:**

1- "No Task Available"

by right-click on the folder, clicking on "Run test", it creates a configuration that does not work.

The issue seems to be that Android Studio doesn't recognised "kotlin" as a valid language for testing. By renaming the folder "kotlin" within the test to "java", it is now possible to run it.

2- Test run on device, not on JUnit
- when started the test, it will try to run it by starting the emulator. It should instead run it on the JVM like any other android JUnit test. It's because the "Run/Debug configuration" is using a "Android Instrumented Tests" instead of "JUnit" configuration.
By trying to manually setup a JUnit configuration, the module Android Test does not appear.

By running the CLI "./gradlew :shared:tasks", I am missing some configurations (it should contains "androidTest" - Executes unit tests for target Android.):

```
Verification tasks
------------------
allTests - Runs the tests for all targets and create aggregated report
check - Runs all checks.
connectedAndroidTest - Installs and runs instrumentation tests for all flavors on connected devices.
connectedCheck - Runs all device checks on currently connected devices.
connectedDebugAndroidTest - Installs and runs the tests for debug on connected devices.
deviceAndroidTest - Installs and runs instrumentation tests using all Device Providers.
deviceCheck - Runs all device checks using Device Providers and Test Servers.
iosX64Test - Executes Kotlin/Native unit tests for target iosX64.
lint - Runs lint on all variants.
lintDebug - Runs lint on the Debug build.
lintRelease - Runs lint on the Release build.
test - Run unit tests for all variants.
testDebugUnitTest - Run unit tests for the debug build.
testReleaseUnitTest - Run unit tests for the release build.
```

----------------

```
Build: AI-203.7717.56.2031.7435690, 202106072248,

AI-203.7717.56.2031.7435690, JRE 11.0.10+0-b96-7281165x64 JetBrains s.r.o., OS Mac OS X(x86_64) v11.2.3, screens 3584.0x2240.0; Retina

AS: Arctic Fox | 2020.3.1 Beta 4; Kotlin plugin: 203-1.5.10-release-891-AS7717.8; Android Gradle Plugin: 4.0.1; Gradle: 6.5; Gradle JDK: version 11.0.10; NDK: from local.properties: (not specified), latest from SDK: (not found); LLDB: pinned revision 3.1 not found, latest from SDK: (package not found); CMake: from local.properties: (not specified), latest from SDK: (not found), from PATH: (not found)
```

Inizia da shared/src/androidTest/kotlin/com/jetbrains/kmm/shared/androidTest.kt e ispeziona la configurazione dei test Android e i task Gradle generati. Esegui ./gradlew :shared:tasks e confronta i task unit-test e connected-test disponibili con il comportamento Android JUnit previsto. Il lavoro è completato quando i test Android di shared vengono riconosciuti ed eseguiti sulla JVM tramite una configurazione JUnit anziché su un dispositivo.

Scritto dal modello di indicizzazione a partire dal testo della issue.