[Wasm] Fix invalid cast generation for inline classes

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

@@ -0,0 +1,8 @@
+// WITH_STDLIB
+// WORKS_WHEN_VALUE_CLASS
+// LANGUAGE: +ValueClasses
+
+inline class X(val i: Int)
+fun unbox(x: X?): Int = checkNotNull(x).i
+
+fun box(): String = if (unbox(X(42)) == 42) "OK" else "Fail"