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/debugger/debugger.c

@@ -1445,13 +1445,11 @@ jerry_debugger_exception_object_to_string (ecma_value_t exception_obj_value) /**
       string_id = LIT_MAGIC_STRING_TYPE_ERROR_UL;
       break;
     }
-#if JERRY_ESNEXT
     case ECMA_BUILTIN_ID_AGGREGATE_ERROR_PROTOTYPE:
     {
       string_id = LIT_MAGIC_STRING_AGGREGATE_ERROR_UL;
       break;
     }
-#endif /* JERRY_ESNEXT */
     case ECMA_BUILTIN_ID_URI_ERROR_PROTOTYPE:
     {
       string_id = LIT_MAGIC_STRING_URI_ERROR_UL;