FIR: dump nested classes in loadJava tests

Because those test are single Java files, many of them use a top-level
class as a container for multiple classes to be tested. Such tests do
almost nothing if those nested classes aren't handled.

compiler/testData/loadJava/compiledJava/annotations/NestedEnumArgument.fir.txt

@@ -3,4 +3,17 @@ public open class NestedEnumArgument : R|kotlin/Any| {
 
     public constructor(): R|test/NestedEnumArgument|
 
+    public final annotation class Anno : R|kotlin/Annotation| {
+        public constructor(value: R|test/NestedEnumArgument.E|): R|test/NestedEnumArgument.Anno|
+
+    }
+    public final enum class E : R|kotlin/Enum<ft<test/NestedEnumArgument.E, test/NestedEnumArgument.E?>>| {
+        public final static enum entry FIRST: R|@EnhancedNullability test/NestedEnumArgument.E|
+        public final static fun values(): R|kotlin/Array<test/NestedEnumArgument.E>| {
+        }
+
+        public final static fun valueOf(value: R|kotlin/String|): R|test/NestedEnumArgument.E| {
+        }
+
+    }
 }