IrConstTransformer: handle vararg with spread elements properly

compiler/testData/codegen/box/collectionLiterals/collectionLiteralsWithVarargs.kt

@@ -1,5 +1,4 @@
 // WITH_REFLECT
-// IGNORE_BACKEND_FIR: JVM_IR
 // TARGET_BACKEND: JVM
 
 import java.util.Arrays

compiler/testData/ir/irText/declarations/annotations/spreadOperatorInAnnotationArguments.fir.txt

@@ -29,5 +29,5 @@ FILE fqName:<root> fileName:/spreadOperatorInAnnotationArguments.kt
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any
   FUN name:test visibility:public modality:FINAL <> () returnType:kotlin.Unit
     annotations:
-      A(xs = [SPREAD_ELEMENT, SPREAD_ELEMENT])
+      A(xs = ['a', 'b'])
     BLOCK_BODY