[KLIB][tests] Reorganize "klib dump-metadata" tests

- Keep the test data under "native/native.tests/testData/klib/" dir
- Rename tests from "klib contents" to "klib dump-metadata"

native/native.tests/testData/klib/dump-metadata/builtinsSerializer/annotatedEnumEntry.kt

@@ -0,0 +1,14 @@
+package test
+
+annotation class Anno(val value: String = "0", val x: Int = 0)
+annotation class Bnno
+
+enum class Eee {
+    @Anno()
+    Entry1,
+    Entry2,
+    @Anno("3") @Bnno
+    Entry3,
+    @Anno("4", 4)
+    Entry4,
+}