[FIR] Support for EXPOSED_FUNCTION_RETURN_TYPE

compiler/fir/analysis-tests/testData/resolve/visibility/exposedFunctionReturnType.kt

@@ -0,0 +1,9 @@
+class A {
+    private class InnerA {
+
+    }
+}
+
+abstract class B {
+    <!FIR_EXPOSED_FUNCTION_RETURN_TYPE!>fun foo(str: String): A.InnerA<!>
+}

compiler/fir/analysis-tests/testData/resolve/visibility/exposedFunctionReturnType.txt

@@ -0,0 +1,23 @@
+FILE: exposedFunctionReturnType.kt
+    public final class A : R|kotlin/Any| {
+        public constructor(): R|A| {
+            super<R|kotlin/Any|>()
+        }
+
+        private final class InnerA : R|kotlin/Any| {
+            public[private] constructor(): R|A.InnerA| {
+                super<R|kotlin/Any|>()
+            }
+
+        }
+
+    }
+    public abstract class B : R|kotlin/Any| {
+        public constructor(): R|B| {
+            super<R|kotlin/Any|>()
+        }
+
+        public final fun foo(str: R|kotlin/String|): R|A.InnerA|
+
+    }
+