add ultra-light classes/members that work without backend in simple cases

compiler/testData/asJava/ultraLightClasses/simpleFunctions.kt

@@ -0,0 +1,13 @@
+class Foo {
+  open fun bar(a: Int, b:Any, c:Foo): Unit {}
+  internal fun bar2(a: Sequence, b: Unresolved) {}
+  private fun bar3(x: Foo.Inner, vararg y: Inner) = "str"
+  fun bar4() = 42
+
+  public fun nullableVararg(vararg o: Any?): Unit
+
+  operator fun plus(increment: Int): Foo {}
+  fun String.onString(a: (Int) -> Any?): Foo {}
+
+  class Inner {}
+}