Generate is check for inline classes same as for primitives

Should be improved when inline class is based on non-null reference

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

@@ -0,0 +1,55 @@
+// !LANGUAGE: +InlineClasses
+
+inline class UInt(val u: Int) {
+    override fun toString(): String {
+        return "UInt: $u"
+    }
+}
+
+fun Any.isUInt(): Boolean = this is UInt
+fun Any.notIsUInt(): Boolean = this !is UInt
+
+inline fun <reified T> Any?.instanceOf(): Boolean = this is T
+
+fun UInt.extension(): String = "OK:"
+
+fun foo(x: UInt?): String {
+    if (x is UInt) {
+        return x.extension() + x.toString()
+    }
+
+    return "fail"
+}
+
+fun bar(x: UInt?): String {
+    if (x is Any) {
+        return x.extension()
+    }
+
+    return "fail"
+}
+
+fun box(): String {
+    val u = UInt(12)
+    if (!u.isUInt()) return "fail"
+    if (u.notIsUInt()) return "fail"
+
+    if (1.isUInt()) return "fail"
+    if (!1.notIsUInt()) return "fail"
+
+
+    if (!u.instanceOf<UInt>()) return "fail"
+    if (1.instanceOf<UInt>()) return "fail"
+
+    val nullableUInt: UInt? = UInt(10)
+    if (!nullableUInt.instanceOf<UInt>()) return "fail"
+
+    val nullAsUInt: UInt? = null
+    if (nullAsUInt.instanceOf<UInt>()) return "fail"
+    if (!nullAsUInt.instanceOf<UInt?>()) return "fail"
+
+    if (foo(u) != "OK:UInt: 12") return "fail"
+    if (bar(u) != "OK:") return "fail"
+
+    return "OK"
+}