Support default arguments and varargs for callable references

#KT-8834
 #KT-19869
 #KT-25514

compiler/testData/codegen/box/callableReference/varargAndDefaults/simpleEmptyVararg.kt

@@ -0,0 +1,11 @@
+// !LANGUAGE: +NewInference
+// IGNORE_BACKEND: JS, JS_IR, JVM_IR
+
+fun foo(x: String, vararg y: String): String =
+        if (y.size == 0) x + "K" else "Fail"
+
+fun call(f: (String) -> String, x: String): String = f(x)
+
+fun box(): String {
+    return call(::foo, "O")
+}