[K/N] Migrate some cinterop tests to new test infra

native/native.tests/testData/CInterop/executable/kt44283/kt44283.def

@@ -0,0 +1,25 @@
+---
+#include <stdlib.h>
+#include <pthread.h>
+
+typedef struct {
+    int d;
+} TestStruct;
+
+typedef struct {
+    void (*f)(TestStruct data);
+} ThreadData;
+
+void *dispatch(void *rawArg) {
+    ThreadData *arg = rawArg;
+    arg->f((TestStruct) {.d = 1});
+    return NULL;
+}
+
+void invokeFromThread(void (*f)(TestStruct data)) {
+    pthread_t thread_id;
+    ThreadData *threadData = malloc(sizeof(ThreadData));
+    threadData->f = f;
+    pthread_create(&thread_id, NULL, dispatch, (void *) threadData);
+    pthread_join(thread_id, NULL);
+}

native/native.tests/testData/CInterop/executable/kt44283/kt44283.kt

@@ -0,0 +1,24 @@
+@file:OptIn(kotlin.native.runtime.NativeRuntimeApi::class)
+
+import kotlinx.cinterop.*
+import kt44283.*
+import kotlin.concurrent.AtomicInt
+import kotlin.test.*
+
+val callbackCounter = AtomicInt(0)
+
+@ExperimentalForeignApi
+fun main() {
+    val func = staticCFunction<CValue<TestStruct>, Unit> {
+        kotlin.native.runtime.GC.collect() // Helps to ensure that "runtime" is already initialized.
+
+        memScoped {
+            println("Hello, Kotlin/Native! ${it.ptr.pointed.d}")
+        }
+        callbackCounter.incrementAndGet()
+    }
+
+    assertEquals(0, callbackCounter.value)
+    invokeFromThread(func.reinterpret())
+    assertEquals(1, callbackCounter.value)
+}