Use JVM platform if the source-set is shared between jvm and android-jvm targets (#4258)

* Infer analysis platform as `JVM` if the source-set is shared between jvm and android-jvm
* Add IT for android+jvm shared classes case

Author: whyoleg

build.gradle.kts

@@ -123,6 +123,7 @@ idea {
 
                 "dokka-integration-tests/gradle/src/testExampleProjects/expectedData",
                 "dokka-integration-tests/gradle/projects/it-android/expectedData",
+                "dokka-integration-tests/gradle/projects/it-multiplatform-android-jvm/expectedData",
                 "dokka-integration-tests/gradle/projects/it-android-compose/expectedData",
                 "dokka-integration-tests/gradle/projects/it-kotlin-multiplatform/expectedData",
 

dokka-integration-tests/gradle/projects/it-multiplatform-android-jvm/build.gradle.kts

@@ -0,0 +1,28 @@
+plugins {
+    id("com.android.library") version "/* %{AGP_VERSION} */"
+    id("org.jetbrains.dokka") version "/* %{DGP_VERSION} */"
+    kotlin("multiplatform") version "/* %{KGP_VERSION} */"
+}
+
+android {
+    namespace = "org.jetbrains.dokka.it.android"
+    defaultConfig {
+        minSdkVersion(21)
+        setCompileSdkVersion(29)
+    }
+}
+
+kotlin {
+    jvm()
+    androidTarget()
+
+    sourceSets {
+        val androidAndJvmMain by registering
+        jvmMain {
+            dependsOn(androidAndJvmMain.get())
+        }
+        androidMain {
+            dependsOn(androidAndJvmMain.get())
+        }
+    }
+}