Converter tests:

Change test data files extension to "java"

j2k/tests/testData/ast/issues/kt-828.java

@@ -0,0 +1,16 @@
+//file
+class Test {
+  void test() {
+    boolean res = true;
+    res &= false;
+    res |= false;
+    res ^= false;
+    System.out.println(true & false);
+    System.out.println(true | false);
+    System.out.println(true ^ false);
+    System.out.println(!true);
+
+    System.out.println(true && false);
+    System.out.println(true || false);
+  }
+}