[Native] Move hasNonConstInitializer from IrUtils2

This function could be useful for other backends.

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/ir/util/IrUtils2.kt

@@ -31,6 +31,3 @@ fun IrBuilderWithScope.irCatch() =
                         isLateinit = false
                 )
         )
-
-val IrField.hasNonConstInitializer: Boolean
-    get() = initializer?.expression.let { it != null && it !is IrConst<*> && it !is IrConstantValue }