[KLIB][tests] Keep "klib evolution" test data under "testData/klib/" dir

compiler/testData/klib/evolution/turnClassIntoDataClass.kt

@@ -0,0 +1,46 @@
+// MODULE: lib
+// FILE: A.kt
+// VERSION: 1
+
+interface A {
+    fun foo(): String
+    val bar: String
+}
+
+class X(val a: String, var b: String) {
+    fun foo(): String = "original class' method"
+    val bar: String = "original class' property"
+}
+
+// FILE: B.kt
+// VERSION: 2
+
+interface A {
+    fun foo(): String
+    val bar: String
+}
+
+data class X(val a: String, var b: String) {
+    fun foo(): String = a + b
+    val bar: String = b + a
+}
+
+// MODULE: mainLib(lib)
+// FILE: mainLib.kt
+
+fun lib(): String {
+    val x = X("first", "second")
+    return when {
+        x.a != "first" -> "fail 1"
+        x.b != "second" -> "fail 2"
+        x.foo() != "firstsecond" -> "fail 3"
+        x.bar != "secondfirst" -> "fail 4"
+        x.toString() != "X(a=first, b=second)" -> "fail 5"
+        else -> "OK"
+    }
+}
+
+// MODULE: main(mainLib)
+// FILE: main.kt
+fun box(): String = lib()
+