[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/propertyAccessorAnnotations.kt

@@ -0,0 +1,10 @@
+package test
+
+annotation class Anno(val value: String)
+
+@Anno("property") val v1 = ""
+
+var v2: String
+    @Anno("getter") get() = ""
+    @Anno("setter") set(@Anno("setparam") value) {
+    }