Support unboxing of inline classes in elvis

compiler/testData/codegen/bytecodeText/inlineClasses/unboxInlineClassAfterElvis.kt

@@ -0,0 +1,14 @@
+// !LANGUAGE: +InlineClasses
+
+inline class UInt(private val u: Int)
+
+fun test(x: UInt?, y: UInt) {
+    val a = x ?: y // unbox
+    val b = x ?: x!! // unbox unbox
+}
+
+// 0 INVOKESTATIC UInt\$Erased.box
+// 3 INVOKEVIRTUAL UInt.unbox
+
+// 0 valueOf
+// 0 intValue