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

tests/jerry/es.next/let7.js

@@ -0,0 +1,84 @@
+/* Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+assert (typeof f === "undefined");
+
+function g() { return 6; }
+
+switch (g()) {
+case f():
+
+  let g = 9;
+
+  assert (g === 9);
+
+  function f() { return 6; }
+  break;
+
+default:
+  assert (false);
+}
+
+assert (f() === 6);
+
+switch (g()) {
+case f() - 2:
+
+  let g = 9;
+
+  assert ((function() { return g + f(); })() === 17);
+
+  function f() { return 8; }
+  break;
+
+default:
+  assert (false);
+}
+
+assert (f() === 8);
+
+switch (g()) {
+case g() + 5:
+  {
+    let g = 4;
+    assert (g == 4);
+  }
+  break;
+
+default:
+  /* If the declaration is not "executed", it has no effect */
+  function g() { return 1; }
+  assert (false);
+}
+
+assert (g() === 6);
+
+switch (g()) {
+case g() * 2:
+  {
+    let g = 4;
+    assert (g == 4);
+    eval();
+  }
+
+  function g() { return 3; }
+  break;
+
+default:
+  assert (false);
+}
+
+assert (g() === 3);