[klib] Disable ManglerChecker on K2

`ManglerChecker` is a class that verifies that for each IR declaration
(except some, see its `needsChecking` property) its mangled name
(computed from IR) is the same as the mangled name computed from its
frontend representation — `DeclarationDescriptor` on K1 or
`FirDeclaration` on K2.

The way it does it is as follows.

On K1, `ManglerChecker` looks if the declaration has a true,
non-IR-based descriptor, it if it does, then it checks it
(see ManglerChecker.Companion#hasDescriptor).

On K2, since we don’t have any descriptors, `ManglerChecker` looks if
the declaration’s metadata property is `null` (because the corresponding
`FirDeclaration` is stored there). If it’s not, it checks it
(see ManglerChecker.Companion#hasMetadata).

The issue is that those two conditions are not equivalent.

When the Compose compiler plugin transforms an IR function, it copies
its `metadata` property (as it should, because `metadata` can contain
anything, not necessarily the frontend representation), but doesn't set
the descriptor. Because of that, on K1 that transformed function is
skipped in `ManglerChecker`, and on K2 it’s not.

The correct usage would be to properly distinguish which declarations
come from the FE as is, and which are transformed/synthesized,
and skip the latter. But it is unclear how to implement this.

For now, the easiest way to fix this on K2 is to not run ManglerChecker
at all.

KT-60648
^KT-59448 Fixed

compiler/ir/serialization.common/src/org/jetbrains/kotlin/backend/common/serialization/mangle/ManglerChecker.kt

@@ -22,7 +22,6 @@ class ManglerChecker(
 
     companion object {
         val hasDescriptor: (IrDeclarationBase) -> Boolean = { it.symbol.hasDescriptor }
-        val hasMetadata: (IrDeclarationBase) -> Boolean = { (it as? IrMetadataSourceOwner)?.metadata != null }
     }
 
     private val manglers = _manglers.toList()

kotlin-native/backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/Fir2Ir.kt

@@ -93,7 +93,11 @@ internal fun PhaseContext.fir2Ir(
             fir2IrResultPostCompute = {
                 // it's important to compare manglers before actualization, since IR will be actualized, while FIR won't
                 irModuleFragment.acceptVoid(
-                        ManglerChecker(KonanManglerIr, Ir2FirManglerAdapter(FirNativeKotlinMangler()), needsChecking = ManglerChecker.hasMetadata)
+                        ManglerChecker(
+                                KonanManglerIr,
+                                Ir2FirManglerAdapter(FirNativeKotlinMangler()),
+                                needsChecking = { false }, // FIXME(KT-60648): Re-enable
+                        )
                 )
             }
     ).also {