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-jobqueue.c

@@ -26,8 +26,6 @@
 #include "opcodes.h"
 #include "vm-stack.h"
 
-#if JERRY_ESNEXT
-
 /**
  * Mask for job queue type.
  */
@@ -637,4 +635,3 @@ ecma_free_all_enqueued_jobs (void)
  * @}
  * @}
  */
-#endif /* JERRY_ESNEXT */