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/builtin-objects/ecma-builtin-helpers-macro-defines.inc.h

@@ -25,7 +25,7 @@
 #define STRING_VALUE(name, magic_string_id, prop_attributes)
 #endif /* !STRING_VALUE */
 
-#if ENABLED (JERRY_ES2015)
+#if ENABLED (JERRY_ESNEXT)
 #ifndef SYMBOL_VALUE
 #define SYMBOL_VALUE(symbol, desc_magic_string_id)
 #endif /* !SYMBOL_VALUE */
@@ -37,7 +37,7 @@
 #ifndef ACCESSOR_BUILTIN_FUNCTION_OBJECT
 #define ACCESSOR_BUILTIN_FUNCTION_OBJECT(name, getter_builtin_id, setter_builtin_id, prop_attributes)
 #endif /* !ACCESSOR_BUILTIN_FUNCTION_OBJECT */
-#endif /* ENABLED (JERRY_ES2015) */
+#endif /* ENABLED (JERRY_ESNEXT) */
 
 #ifndef OBJECT_VALUE
 #define OBJECT_VALUE(name, obj_builtin_id, prop_attributes)