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

targets/nuttx-stm32f4/README.md

@@ -44,7 +44,7 @@ jerryscript/tools/build.py \
     --jerry-libm=ON \
     --all-in-one=ON \
     --mem-heap=70 \
-    --profile=es2015-subset \
+    --profile=es.next \
     --compile-flag="--sysroot=${PWD}/nuttx" \
     --toolchain=${PWD}/jerryscript/cmake/toolchain_mcu_stm32f4.cmake
 ```