Java to Kotlin converter: replacing equals call to ==/!= and no redundant parethesis generation

#KT-4426 Fixed

j2k/tests/testData/ast/equals/Equals1.java

@@ -0,0 +1,13 @@
+//file
+interface I {
+}
+
+class C{
+    boolean foo1(I i1, I i2) {
+        return i1.equals(i2)
+    }
+
+    boolean foo2(I i1, I i2) {
+        return !i1.equals(i2)
+    }
+}