K/N: enable -Xlambdas=class for :kotlin-native:Interop:Indexer

`staticCFunction` is used a few times in this module, and it uses
kotlin-reflect to inspect the lambda parameter, which is only possible
for class-generated lambdas.

This is needed to enable indy lambdas in the project.

kotlin-native/Interop/Indexer/build.gradle.kts

@@ -169,6 +169,8 @@ tasks.withType<org.jetbrains.kotlin.gradle.tasks.KotlinCompile>().configureEach
                 "-Xskip-prerelease-check",
                 "-opt-in=kotlinx.cinterop.BetaInteropApi",
                 "-opt-in=kotlinx.cinterop.ExperimentalForeignApi",
+                // staticCFunction uses kotlin.reflect.jvm.reflect on its lambda parameter.
+                "-Xlambdas=class",
         )
 
     }