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

compiler/testData/klib/partial-linkage/referencingUnusableDeclarations/lib1/l1.kt

@@ -0,0 +1,21 @@
+open class RemovedClass {
+    val p1 = "p1"
+    fun f1() = "f1"
+}
+
+interface RemovedInterface {
+    val p1: String
+    val p2 get() = "p2"
+    fun f1(): String
+    fun f2() = "f2"
+}
+
+class ClassWithChangedMembers {
+    fun removedFun() = "removedFun"
+    fun changedFun(x: String) = x
+}
+
+interface InterfaceWithChangedMembers {
+    fun removedFun() = "removedFun"
+    fun changedFun(x: String) = x
+}

compiler/testData/klib/partial-linkage/referencingUnusableDeclarations/lib1/l1.kt.1

@@ -0,0 +1,23 @@
+//open class RemovedClass {
+//    val p1 = "p1"
+//    fun f1() = "f1"
+//}
+
+//interface RemovedInterface {
+//    val p1: String
+//    val p2 get() = "p2"
+//    fun f1(): String
+//    fun f2() = "f2"
+//}
+
+class ClassWithChangedMembers {
+//    fun removedFun() = "removedFun"
+//    fun changedFun(x: String) = x
+    fun changedFun(x: Int) = x.toString()
+}
+
+interface InterfaceWithChangedMembers {
+//    fun removedFun() = "removedFun"
+//    fun changedFun(x: String) = x
+    fun changedFun(x: Int) = x.toString()
+}

compiler/testData/klib/partial-linkage/referencingUnusableDeclarations/lib1/module.info

@@ -0,0 +1,6 @@
+STEP 0:
+    dependencies: stdlib
+STEP 1:
+    dependencies: stdlib
+    modifications:
+        U : l1.kt.1 -> l1.kt