kotlinx.atomicfu compiler plugin for JS_IR backend (#4581)

* kotlinx.atomicfu compiler plugin for JS_IR

Support transformations of atomic operations introduced by the kotlinx.atomicfu library for the JS_IR backend. Compiler plugin is applied externally by the kotlinx.atomicfu gradle plugin.

* Apply compiler plugin for JS platform only

* New plugin test structure

* testGroupOutputDirPrefix changed

plugins/atomicfu/atomicfu-compiler/testData/box/ArrayInlineFunctionTest.kt

@@ -0,0 +1,47 @@
+import kotlinx.atomicfu.*
+import kotlin.test.*
+
+class ArrayInlineFunctionTest {
+    private val anyArr = atomicArrayOfNulls<Any?>(5)
+    private val refArr = atomicArrayOfNulls<Box>(5)
+
+    private data class Box(val n: Int)
+
+    fun testSetArrayElementValueInLoop() {
+        anyArr[0].loop { cur ->
+            assertTrue(anyArr[0].compareAndSet(cur, IntArray(5)))
+            return
+        }
+    }
+
+    private fun action(cur: Box?) = cur?.let { Box(cur.n * 10) }
+
+
+    fun testArrayElementUpdate() {
+        refArr[0].lazySet(Box(5))
+        refArr[0].update { cur -> cur?.let { Box(cur.n * 10) } }
+        assertEquals(refArr[0].value!!.n, 50)
+    }
+
+
+    fun testArrayElementGetAndUpdate() {
+        refArr[0].lazySet(Box(5))
+        assertEquals(refArr[0].getAndUpdate { cur -> action(cur) }!!.n, 5)
+        assertEquals(refArr[0].value!!.n, 50)
+    }
+
+
+    fun testArrayElementUpdateAndGet() {
+        refArr[0].lazySet(Box(5))
+        assertEquals(refArr[0].updateAndGet { cur -> action(cur) }!!.n, 50)
+    }
+}
+
+fun box(): String {
+    val testClass = ArrayInlineFunctionTest()
+    testClass.testSetArrayElementValueInLoop()
+    testClass.testArrayElementGetAndUpdate()
+    testClass.testArrayElementUpdate()
+    testClass.testArrayElementUpdateAndGet()
+    return "OK"
+}