Prepare repository for merge into master

j2k/tests/testData/ast/prefixOperator/statement/nullableIf.jav

@@ -0,0 +1,2 @@
+String s = null;
+if (!s.isEmpty()) { }

j2k/tests/testData/ast/prefixOperator/statement/nullableIf.kt

@@ -0,0 +1,4 @@
+var s : String? = null
+if (!s?.isEmpty()!!)
+{
+}