[FIR] Build resolved argument list for augmented array assignment get call

This lets us get rid of some fallback code in FIR2IR that handles
unresolved argument lists.
After this, we should have an invariant that all non-empty argument
lists are resolved when FIR2IR runs.

#KT-66124

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt

@@ -1635,23 +1635,25 @@ open class FirExpressionsResolveTransformer(transformer: FirAbstractBodyResolveT
                 dispatchReceiver = lhsGetCall.dispatchReceiver
             }
             calleeReference = lhsGetCall.calleeReference
-            argumentList = buildArgumentList {
-                var i = 0
-                for (argument in lhsGetCall.argumentList.arguments) {
-                    arguments += if (argument is FirVarargArgumentsExpression) {
-                        buildVarargArgumentsExpression {
-                            val varargSize = argument.arguments.size
-                            arguments += indicesQualifiedAccessForGet.subList(i, i + varargSize)
-                            i += varargSize
-                            source = argument.source
-                            coneTypeOrNull = argument.resolvedType
-                            coneElementTypeOrNull = argument.coneElementTypeOrNull
-                        }
-                    } else {
-                        indicesQualifiedAccessForGet[i++]
+            var i = 0
+            val newMapping = (lhsGetCall.argumentList as FirResolvedArgumentList).mapping.mapKeysTo(LinkedHashMap()) { (argument) ->
+                if (argument is FirVarargArgumentsExpression) {
+                    buildVarargArgumentsExpression {
+                        val varargSize = argument.arguments.size
+                        arguments += indicesQualifiedAccessForGet.subList(i, i + varargSize)
+                        i += varargSize
+                        source = argument.source
+                        coneTypeOrNull = argument.resolvedType
+                        coneElementTypeOrNull = argument.coneElementTypeOrNull
                     }
+                } else {
+                    indicesQualifiedAccessForGet[i++]
                 }
             }
+            argumentList = buildResolvedArgumentList(
+                lhsGetCall.argumentList,
+                newMapping,
+            )
             origin = FirFunctionCallOrigin.Operator
             coneTypeOrNull = lhsGetCall.resolvedType
         }