Minor. Add more tests

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

@@ -0,0 +1,15 @@
+// WITH_STDLIB
+// IGNORE_BACKEND: JVM
+// WORKS_WHEN_VALUE_CLASS
+// LANGUAGE: +ValueClasses, +GenericInlineClassParameter
+
+abstract class C<T> {
+    fun foo(v: T?, x: (T) -> Any?) = v?.let { x(it) }
+}
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class V<T>(val value: T)
+
+class D : C<V<String>>()
+
+fun box() = D().foo(V("OK")) { it.value } as String