JVM IR: Avoid optimizing comparisons between boxed primitives and null

A comparison of the form `x == null` where `x` is of type `Int` might not
be vacuous if `x` is a boxed value coming from Java code.

compiler/testData/codegen/box/platformTypes/unsafeNullCheckWithPrimitive.kt

@@ -1,6 +1,5 @@
 // IGNORE_BACKEND_FIR: JVM_IR
 // TARGET_BACKEND: JVM
-// IGNORE_BACKEND: JVM_IR
 // FILE: Unsound.java
 
 import test.Wrap;
@@ -17,6 +16,4 @@ package test
 
 class Wrap<T>(val x: T)
 
-// JVM IR generates bytecode that fails with NPE because it unwraps the value with `Number.intValue()`,
-// whereas JVM generates a simple null check without unwrapping the box.
 fun box(): String = if ((Unsound.get<Int>() as Wrap<Int>).x == null) "OK" else "Fail"