[K/N] Adjust moved special backend checks tests

^KT-61564

compiler/testData/diagnostics/nativeTests/specialBackendChecks/cInterop/t60.kt

@@ -1,3 +1,5 @@
+// FIR_IDENTICAL
+@file:OptIn(kotlinx.cinterop.ExperimentalForeignApi::class)
 import kotlinx.cinterop.*
 
 class Vertex constructor(rawPtr: NativePtr) : CStructVar(rawPtr) {
@@ -6,5 +8,6 @@ class Vertex constructor(rawPtr: NativePtr) : CStructVar(rawPtr) {
     var r: Float = 0f
     var g: Float = 0f
     var b: Float = 0f
+    @Suppress("DEPRECATION")
     companion object : CStructVar.Type(40, 8)
 }