Re-target for ES.Next (#3901)

A list of changes:
- 'es2015-subset' profile is deprecated, and an 'es.next' profile is added.
- The default profile is changed to 'es.next'
- Renamed the JERRY_ES2015 guard to JERRY_ESNEXT
- Renamed JERRY_ES2015_BUILTIN_* guards to JERRY_BUILTIN_*
- Moved es2015 specific tests to a new 'es.next' subdirectory
- Updated docs, targets, and test runners to reflect these changes

Resolves #3737.

JerryScript-DCO-1.0-Signed-off-by: Dániel Bátyai dbatyai@inf.u-szeged.hu

jerry-core/ecma/operations/ecma-proxy-object.c

@@ -34,7 +34,7 @@
  * @{
  */
 
-#if ENABLED (JERRY_ES2015_BUILTIN_PROXY)
+#if ENABLED (JERRY_BUILTIN_PROXY)
 /**
  * Check whether the argument satifies the requrements of [[ProxyTarget]] or [[ProxyHandler]]
  *
@@ -1810,7 +1810,7 @@ ecma_proxy_object_construct (ecma_object_t *obj_p, /**< proxy object */
   return new_obj;
 } /* ecma_proxy_object_construct */
 
-#endif /* ENABLED (JERRY_ES2015_BUILTIN_PROXY) */
+#endif /* ENABLED (JERRY_BUILTIN_PROXY) */
 
 /**
  * @}