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.

compiler/cli/src/org/jetbrains/kotlin/cli/metadata/MetadataUtils.kt

@@ -22,7 +22,6 @@ fun buildKotlinMetadataLibrary(configuration: CompilerConfiguration, serializedM
         libraryVersion = null,
         compilerVersion = KotlinCompilerVersion.getVersion(),
         metadataVersion = KlibMetadataVersion.INSTANCE.toString(),
-        irVersion = null
     )
 
     buildKotlinLibrary(