[PL] Check visibility of declarations in stdlib

Previously, the PL engine skipped visibility checks for declarations in
the stdlib for optimization reasons. This led to bugs like KT-81995
where the linker didn't complain when Compose plugin generated a private
constructor call in a separate module.

^KT-82213 Fixed

Author: francescoo22

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/linkage/partial/PartiallyLinkedIrTreePatcher.kt

@@ -730,8 +730,8 @@ internal class PartiallyLinkedIrTreePatcher(
                     // OK. Used in the same module.
                     null
                 }
-                containingModule.shouldBeSkipped -> {
-                    // Optimization: Don't check visibility of declarations in stdlib & co.
+                containingModule == PLModule.SyntheticBuiltInFunctions -> {
+                    // Optimization: Don't check the visibility of synthetic built-in functions.
                     null
                 }
                 !declaration.isEffectivelyPrivate() -> {