Fix generation of checkcast instructions for inline classes

Normalize LHS and RHS types to use only boxed ones and then let bytecode
 optmizer reduce redundant boxing

compiler/testData/codegen/box/inlineClasses/inlineClassesCheckCast.kt

@@ -0,0 +1,48 @@
+// !LANGUAGE: +InlineClasses
+
+inline class AsAny<T>(val x: Any?)
+inline class AsInt(val x: Int)
+
+inline fun <reified T> Any?.checkcast(): T = this as T
+
+object Reference {
+    fun <T, R> transform(a: AsAny<T>): AsAny<R> = a as AsAny<R>
+    fun <T, R> transformNullable(a: AsAny<T>?): AsAny<R> = a as AsAny<R>
+    fun <T, R> transformToNullable(a: AsAny<T>): AsAny<R>? = a as AsAny<R>
+    fun <T, R> transformToNullableTarget(a: AsAny<T>): AsAny<R>? = a as AsAny<R>?
+    fun <T, R> transformNullableToNullableTarget(a: AsAny<T>?): AsAny<R>? = a as AsAny<R>?
+}
+
+object Primitive {
+    fun transform(a: AsInt): AsInt = a as AsInt
+    fun transformNullable(a: AsInt?): AsInt = a as AsInt
+    fun transformToNullable(a: AsInt): AsInt? = a as AsInt
+    fun transformToNullableTarget(a: AsInt): AsInt? = a as AsInt?
+    fun transformNullableToNullableTarget(a: AsInt?): AsInt? = a as AsInt?
+}
+
+fun box(): String {
+    val a = AsAny<Int>(42)
+    val b1 = Reference.transform<Int, Number>(a)
+    val b2 = Reference.transformNullable<Int, Number>(a)
+    val b3 = Reference.transformToNullable<Int, Number>(a)
+    val b4 = Reference.transformToNullableTarget<Int, Number>(a)
+    val b5 = Reference.transformNullableToNullableTarget<Int, Number>(a)
+    val b6 = Reference.transformNullableToNullableTarget<Int, Number>(null)
+
+    val b7 = a.checkcast<AsAny<Number>>()
+    if (b7.x != a.x) return "Fail 1"
+
+    val c = AsInt(42)
+    val d1 = Primitive.transform(c)
+    val d2 = Primitive.transformNullable(c)
+    val d3 = Primitive.transformToNullable(c)
+    val d4 = Primitive.transformToNullableTarget(c)
+    val d5 = Primitive.transformNullableToNullableTarget(c)
+    val d6 = Primitive.transformNullableToNullableTarget(null)
+
+    val d7 = c.checkcast<AsInt>()
+    if (d7.x != c.x) return "Fail 2"
+
+    return "OK"
+}