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/operations/ecma-iterator-object.h

@@ -18,8 +18,6 @@
 
 #include "ecma-globals.h"
 
-#if JERRY_ESNEXT
-
 /** \addtogroup ecma ECMA
  * @{
  *
@@ -78,8 +76,6 @@ ecma_value_t ecma_async_from_sync_iterator_unwrap_cb (ecma_object_t *function_ob
                                                       const ecma_value_t args_p[],
                                                       const uint32_t args_count);
 
-#endif /* JERRY_ESNEXT */
-
 /**
  * @}
  * @}