Fix IrFunction.isEmptyArray implementation

The previous one was incorrect for K1 since parent of top-level function
is `IrClass`, not `IrPackageFragment`.

The change is non-functional, K1 still worked correctly, but had to do
some extra work when inlining `emptyArray` calls and produces less
performant bytecode.

compiler/testData/codegen/boxInline/property/fromObject.kt

@@ -1,5 +1,5 @@
 // WITH_STDLIB
-// JVM_ABI_K1_K2_DIFF: KT-62465
+// JVM_ABI_K1_K2_DIFF: KT-66000
 
 // FILE: 1.kt
 package test