Fix mapping of nullable generic underlying types of inline classes

#KT-32162 Fixed

compiler/testData/codegen/box/inlineClasses/nullableWrapperEqualityGeneric2.kt

@@ -0,0 +1,25 @@
+// WITH_STDLIB
+// WORKS_WHEN_VALUE_CLASS
+// IGNORE_BACKEND: JVM
+// LANGUAGE: +ValueClasses, +GenericInlineClassParameter
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class Z1<T: String>(val x: T)
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class ZN<T: Z1<String>>(val z: T?)
+
+OPTIONAL_JVM_INLINE_ANNOTATION
+value class ZN2<TN: ZN<Z1<String>>>(val z: TN)
+
+fun zap(b: Boolean): ZN2<ZN<Z1<String>>>? = if (b) null else ZN2(ZN(null))
+
+fun eq(a: Any?, b: Any?) = a == b
+
+fun box(): String {
+    val x = zap(true)
+    val y = zap(false)
+    if (eq(x, y)) throw AssertionError()
+
+    return "OK"
+}