Move everything under kotlin-native folder

I was forced to manually do update the following files, because otherwise
they would be ignored according .gitignore settings. Probably they
should be deleted from repo.

Interop/.idea/compiler.xml
Interop/.idea/gradle.xml
Interop/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_runtime_1_0_3.xml
Interop/.idea/libraries/Gradle__org_jetbrains_kotlin_kotlin_stdlib_1_0_3.xml
Interop/.idea/modules.xml
Interop/.idea/modules/Indexer/Indexer.iml
Interop/.idea/modules/Runtime/Runtime.iml
Interop/.idea/modules/StubGenerator/StubGenerator.iml
backend.native/backend.native.iml
backend.native/bc.frontend/bc.frontend.iml
backend.native/cli.bc/cli.bc.iml
backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2Native.kt
backend.native/cli.bc/src/org/jetbrains/kotlin/cli/bc/K2NativeCompilerArguments.kt
backend.native/tests/link/lib/foo.kt
backend.native/tests/link/lib/foo2.kt
backend.native/tests/teamcity-test.property

kotlin-native/backend.native/tests/codegen/bridges/test17.kt

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+
+package codegen.bridges.test17
+
+import kotlin.test.*
+
+// abstract bridge
+interface A<T> {
+    fun foo(): T
+}
+
+abstract class B<T>: A<T>
+
+abstract class C: B<Int>()
+
+class D: C() {
+    override fun foo(): Int {
+        return 42
+    }
+}
+
+@Test fun runTest() {
+    val d = D()
+    val c: C = d
+    val b: B<Int> = d
+    val a: A<Int> = d
+    println(d.foo())
+    println(c.foo())
+    println(b.foo())
+    println(a.foo())
+}