FIR IDE: move analysis api fir testdata to the analysis directory

analysis/analysis-api/testData/components/declarationRenderer/nestedClass.kt

@@ -0,0 +1,7 @@
+abstract class Base(val s: String)
+
+class Outer {
+    class Derived(s: String) : Base(s)
+
+    object Obj : Base("")
+}