tests: added eqeq test

tests: sum-test: emproved test sum of int with various types of second argument (byte, short and etc)
tests: hello2 minor fix in test

backend.native/tests/build.gradle

@@ -172,12 +172,13 @@ task hello1(type: RunKonanTest) {
     source = "runtime/basic/hello1.kt"
 }
 
-/* TODO: enable, once calling plus operator is implemented.
+/*
 task hello2(type: RunKonanTest) {
-    goldValue = "Hello World"
+    goldValue = "you entered 'Hello World'"
     testData = "Hello World"
     source = "runtime/basic/hello2.kt"
-} */
+}
+*/
 
 /* TODO: enable, once can call toString() on Int.
 task hello3(type: RunKonanTest) {