[atomicfu-K/N] Tests for K/N atomicfu-compiler-plugin

* `nativeTest` task now allows to provide compiler plugins that may be enabled during test compilation
* test sets for JVM and K/N backends are equal

KT-60800 describes all the issues with native tests that were solved in this commit.

Co-authored-by: Dmitriy Dolovov <Dmitriy.Dolovov@jetbrains.com>

Merge-request: KT-MR-11401
Merged-by: Maria Sokolova <maria.sokolova@jetbrains.com>

plugins/atomicfu/atomicfu-compiler/testData/nativeBox/atomics_basic/MultiInitTest.kt

@@ -0,0 +1,30 @@
+import kotlinx.atomicfu.*
+import kotlin.test.*
+
+class MultiInitTest {
+    fun testBasic() {
+        val t = MultiInit()
+        check(t.incA() == 1)
+        check(t.incA() == 2)
+        check(t.incB() == 1)
+        check(t.incB() == 2)
+    }
+}
+
+class MultiInit {
+    private val a = atomic(0)
+    private val b = atomic(0)
+
+    fun incA() = a.incrementAndGet()
+    fun incB() = b.incrementAndGet()
+
+    companion object {
+        fun foo() {} // just to force some clinit in outer file
+    }
+}
+
+@Test
+fun box() {
+    val testClass = MultiInitTest()
+    testClass.testBasic()
+}