[PowerAssert] Add codegen tests

plugins/power-assert/testData/codegen/kotlin-test/AssertNotNullMessageVariable.kt

@@ -0,0 +1,9 @@
+// FUNCTION: kotlin.test.assertNotNull
+
+import kotlin.test.assertNotNull
+
+fun box() = expectThrowableMessage {
+    val name: String? = null
+    val message = "Message:"
+    assertNotNull(name, message)
+}