Converter tests:

Change test data files extension to "java"

j2k/tests/testData/ast/issues/kt-543.java

@@ -0,0 +1,11 @@
+//file
+package demo;
+
+class Test {
+  void putInt(int i) {}
+
+  void test() {
+    byte b = 10;
+    putInt(b);
+  }
+}