Calculate default mask shift properly

#KT-18689 Fixed

compiler/testData/codegen/boxInline/defaultValues/kt18689_4.kt

@@ -0,0 +1,21 @@
+// FILE: 1.kt
+
+package test
+
+class Foo {
+    fun foo() = "OK"
+}
+
+inline fun inlineFn(crossinline fn: () -> String, x: Long = 1L): String {
+    return fn()
+}
+
+// FILE: 2.kt
+
+import test.*
+
+private val foo = Foo()
+
+fun box(): String {
+    return inlineFn(foo::foo)
+}