[FIR2IR] Run constant evaluation before IR extensions

Test `constValInSerialName` in serialization still fails but because of
  different reason

^KT-54994 Fixed

plugins/kotlinx-serialization/testData/boxIr/constValInSerialName.kt

@@ -0,0 +1,20 @@
+// WITH_STDLIB
+// ISSUE: KT-54994
+
+import kotlinx.serialization.*
+import kotlinx.serialization.json.*
+import kotlinx.serialization.internal.*
+
+const val prefix = "foo"
+
+@Serializable
+data class Bar(@SerialName("$prefix.bar") val bar: String)
+
+fun box(): String {
+    val expectedBar = Bar("hello")
+    val json = Json.encodeToString(Bar.serializer(), expectedBar)
+    if (json != """{"foo.bar":"hello"}""") return "Fail: $json"
+    val actualBar = Json.decodeFromString(Bar.serializer(), json)
+    if (expectedBar != actualBar) return "Fail: $actualBar"
+    return "OK"
+}