Add regression tests for obsolete issues

#KT-9304
 #KT-14961
 #KT-16549
 #KT-21080
 #KT-28234
 #KT-30102
 #KT-31994
 #KT-34291
 #KT-38099
 #KT-41174
 #KT-44622
 #KT-44701
 #KT-44781
 #KT-44849
 #KT-44978
 #KT-45081
 #KT-45286
 #KT-45383
 #KT-45444
 #KT-45907

compiler/testData/codegen/box/funInterface/kt45444_privateFunInterface.kt

@@ -0,0 +1,16 @@
+// IGNORE_BACKEND: JVM
+// DONT_TARGET_EXACT_BACKEND: WASM
+// WASM_MUTE_REASON: SAM_CONVERSIONS
+
+private fun interface Listener {
+    fun onChanged(): String
+}
+
+private class Foo {
+    private val listener = Listener { "OK" }
+    val result = listener.onChanged()
+}
+
+private val foo = Foo()
+
+fun box(): String = foo.result