j2k: flatten test cases and testData directory structure

Move j2k/test/tests -> j2k/tests, j2k/test/testData -> j2k/testData

j2k/testData/KotlinApi.kt

@@ -0,0 +1,49 @@
+package kotlinApi
+
+public open class KotlinClass(public var field: Int) {
+    public var property: String = ""
+    public var nullableProperty: String? = ""
+
+    public open fun foo(mutableCollection: MutableCollection<String>, nullableCollection: Collection<Int>?): MutableList<Any> = arrayListOf()
+
+    class object {
+        public fun staticFun(p: Int): Int = p
+        public var staticVar: Int = 1
+        public var staticProperty: Int
+            get() = 1
+            set(value) {}
+
+        public fun nullableStaticFun(p: Int?): Int? = p
+        public var nullableStaticVar: Int? = 1
+    }
+}
+
+public trait KotlinTrait {
+    public fun nullableFun(): String?
+    public fun notNullableFun(): String
+
+    public fun nonAbstractFun(): Int = 1
+}
+
+public fun globalFunction(s: String): String = s
+public fun nullableGlobalFunction(s: String?): String? = s
+public fun globalGenericFunction<T>(t: T): T = t
+
+public fun Int.extensionFunction(): String = toString()
+
+public var globalValue1: Int = 1
+public var globalValue2: Int
+    get() = 0
+    set(value) {}
+
+public var String.extensionProperty: Int
+  get() = 1
+  set(value) {}
+
+public object KotlinObject {
+    public fun foo(): Int = 1
+    public var property1: Int = 1
+    public var property2: Int
+        get() = 1
+        set(value) {}
+}