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-async-generator-object.h

@@ -20,8 +20,6 @@
 
 #include "vm-defines.h"
 
-#if JERRY_ESNEXT
-
 /** \addtogroup ecma ECMA
  * @{
  *
@@ -82,8 +80,6 @@ void ecma_async_generator_finalize (vm_executable_object_t *async_generator_obje
 
 ecma_value_t ecma_await_continue (vm_executable_object_t *async_generator_object_p, ecma_value_t value);
 
-#endif /* JERRY_ESNEXT */
-
 /**
  * @}
  * @}