Remove ES_NEXT macro (#4915)

- remove all '#JERRY_ESNEXT' macro
- remove 5.1 build profile, update test runner accordingly (Note: all builtins are turn on by default)
- move tests from tests/jerry/esnext into tests/jerry, concatenate files with same names
- add skiplist to some snapshot tests that were supported only in 5.1
- fix doxygen issues that were hidden before (bc. of es.next macro)

Co-authored-by: Martin Negyokru negyokru@inf.u-szeged.hu
JerryScript-DCO-1.0-Signed-off-by: Adam Szilagyi aszilagy@inf.u-szeged.hu

jerry-core/ecma/base/ecma-helpers-collection.c

@@ -80,8 +80,6 @@ ecma_collection_free_objects (ecma_collection_t *collection_p) /**< value collec
   ecma_collection_destroy (collection_p);
 } /* ecma_collection_free_objects */
 
-#if JERRY_ESNEXT
-
 /**
  * Free the template literal objects and deallocate the collection
  */
@@ -118,8 +116,6 @@ ecma_collection_free_template_literal (ecma_collection_t *collection_p) /**< val
   ecma_collection_destroy (collection_p);
 } /* ecma_collection_free_template_literal */
 
-#endif /* JERRY_ESNEXT */
-
 /**
  * Free the non-object collection elements and deallocate the collection
  */