[FIR, IR] AbstractExpectActualChecker: drop redundant code

- getCallablesStrongIncompatibility is unused (because it moved to the
  "matcher" KT-62590)
- `checkClassScopesCompatibility` parameter is always `true` or unused

Review: https://jetbrains.team/p/kt/reviews/12750/timeline

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/actualizer/ExpectActualCollector.kt

@@ -234,7 +234,6 @@ private class ExpectActualLinkCollector : IrElementVisitor<Unit, ExpectActualLin
                 expectSymbol,
                 listOf(matched),
                 context,
-                checkClassScopesCompatibility = true,
             )
         }
     }

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/actualizer/IrExpectActualMatchingContext.kt

@@ -557,7 +557,6 @@ internal abstract class IrExpectActualMatchingContext(
         expectClass: RegularClassSymbolMarker,
         actualClass: RegularClassSymbolMarker,
         actualMember: DeclarationSymbolMarker,
-        checkClassScopesCompatibility: Boolean,
     ): Map<out DeclarationSymbolMarker, ExpectActualMatchingCompatibility> = error("Should not be called")
 
     // It's a stub, because not needed anywhere