[PowerAssert] Add codegen tests

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

@@ -0,0 +1,10 @@
+// FUNCTION: kotlin.test.assertEquals
+
+import kotlin.test.assertEquals
+
+fun box() = expectThrowableMessage {
+    val greeting = "Hello"
+    val name = "World"
+    val message = "Message:"
+    assertEquals(greeting, name, message)
+}