[KLIB] Keep "API for KLIB ABI" test data under "compiler/testData/klib/" dir

The test data is used both in ":kotlin-util-klib-abi" and
":native:native.tests" modules. It's better to keep it together with
the test data for other KLIB tests which are also used in more than one
module, i.e. in "compiler/testData/klib/" dir.

compiler/testData/klib/dump-abi/content/classifiers.kt

@@ -0,0 +1,69 @@
+// MODULE: classifiers_library
+
+package classifiers.test
+
+class RegularClass(val property: String) {
+    fun function(): String = ""
+}
+
+annotation class AnnotationClass(val property: String) {
+    //fun function(): String = ""
+}
+
+value class ValueClass(val property: String) {
+    fun function(): String = ""
+}
+
+data class DataClass(val property: String) {
+    fun function(): String = ""
+}
+
+object Object {
+    val property: String = ""
+    fun function(): String = ""
+}
+
+interface Interface {
+    val property: String
+    fun function(): String
+}
+
+fun interface FunctionInterface {
+    //val property: String
+    fun function(): String
+}
+
+enum class EnumClassWithoutEntryClasses {
+    FOO_NO_CLASS, BAR_NO_CLASS, BAZ_NO_CLASS
+}
+
+enum class EnumClassWithEntryClasses {
+    FOO_HAS_CLASS { override fun function() = "" },
+    BAR_NO_CLASS,
+    BAZ_HAS_CLASS { override fun function() = "" };
+
+    open fun function(): String = ""
+}
+
+class CompanionHolder1 {
+    companion object // default name
+}
+class CompanionHolder2 {
+    companion object Companion // custom name
+}
+class CompanionHolder3 {
+    companion object DEFAULT // custom name
+}
+class CompanionHolder4 {
+    object Object // a regular nested object
+}
+
+class TopLevelClass {
+    class Nested {
+        class Nested
+        inner class Inner
+    }
+    inner class Inner {
+        inner class Inner
+    }
+}