Cleanup: drop KlibIrVersion

Review: https://jetbrains.team/p/kt/reviews/8401
In scope of: KT-55082

Because this version isn't used for anything. We have KotlinAbiVersion
to version the IR format.

kotlin-native/klib/src/main/kotlin/org/jetbrains/kotlin/cli/klib/main.kt

@@ -116,7 +116,6 @@ class Library(val libraryNameOrPath: String, val requestedRepository: String?, v
         val headerCompilerVersion = library.versions.compilerVersion
         val headerLibraryVersion = library.versions.libraryVersion
         val headerMetadataVersion = library.versions.metadataVersion
-        val headerIrVersion = library.versions.irVersion
         val moduleName = ModuleDeserializer(library.moduleHeaderData).moduleName
 
         println("")
@@ -126,7 +125,6 @@ class Library(val libraryNameOrPath: String, val requestedRepository: String?, v
         println("Compiler version: ${headerCompilerVersion}")
         println("Library version: $headerLibraryVersion")
         println("Metadata version: $headerMetadataVersion")
-        println("IR version: $headerIrVersion")
 
         if (library is KonanLibrary) {
             val targets = library.targetList.joinToString(", ")