[FIR] Store expressions of receivers inside candidates instead of ReceiverValue

This is needed because of mutable nature of receiver values: implicit
  receiver values can be modified because of smartcasts, but in candidate
  we need to store snapshot of receiver in the form it was at the beginning
  of the resolution

^KT-58823 Fixed

compiler/fir/semantics/src/org/jetbrains/kotlin/fir/declarations/ImplicitReceiverUtils.kt

@@ -9,6 +9,7 @@ import kotlinx.collections.immutable.PersistentList
 import kotlinx.collections.immutable.persistentListOf
 import kotlinx.collections.immutable.toPersistentList
 import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.labelName
 import org.jetbrains.kotlin.fir.resolve.*
 import org.jetbrains.kotlin.fir.resolve.calls.*

compiler/fir/semantics/src/org/jetbrains/kotlin/fir/resolve/calls/AbstractCandidate.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.fir.resolve.calls
 
+import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.resolve.calls.inference.model.ConstraintSystemError
 import org.jetbrains.kotlin.resolve.calls.tasks.ExplicitReceiverKind
@@ -12,8 +13,8 @@ import org.jetbrains.kotlin.resolve.calls.tower.CandidateApplicability
 
 abstract class AbstractCandidate {
     abstract val symbol: FirBasedSymbol<*>
-    abstract val dispatchReceiverValue: ReceiverValue?
-    abstract val chosenExtensionReceiverValue: ReceiverValue?
+    abstract val dispatchReceiver: FirExpression?
+    abstract val chosenExtensionReceiver: FirExpression?
     abstract val explicitReceiverKind: ExplicitReceiverKind
     abstract val callInfo: AbstractCallInfo
     abstract val diagnostics: List<ResolutionDiagnostic>