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/let13.js

@@ -0,0 +1,110 @@
+// 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.
+
+/* Declaring let */
+
+/* Note: l\u0065t is let */
+
+function check_syntax_error (code) {
+  try {
+    eval(code)
+    assert (false)
+  } catch (e) {
+    assert (e instanceof SyntaxError)
+  }
+}
+
+function check_strict_syntax_error (code) {
+  "use strict"
+
+  try {
+    eval(code)
+    assert (false)
+  } catch (e) {
+    assert (e instanceof SyntaxError)
+  }
+}
+
+check_syntax_error("let let = 5")
+check_syntax_error("const [let] = [1]")
+check_syntax_error("const l\u0065t = 6")
+check_syntax_error("let [l\u0065t] = [2]")
+check_syntax_error("l\\u0065t a")
+check_strict_syntax_error("var let = 5")
+check_strict_syntax_error("function let() {}")
+check_strict_syntax_error("for (let in []) ;")
+check_strict_syntax_error("l\\u0065t;")
+
+var let = 1
+assert(let === 1)
+
+var [let] = [2]
+assert(let === 2)
+
+var x = 0;
+let = [ () => x = 1 ]
+
+l\u0065t[0]()
+assert(x === 1)
+
+function f1()
+{
+  var a = 0
+
+  function let(l\u0065t) {
+    a = let
+  }
+
+  let(3)
+
+  assert(a === 3)
+}
+f1()
+
+function f2()
+{
+  var let = [1]
+
+  /* First: destructuring pattern definition */
+  let
+  [a] = [2]
+
+  assert(a === 2)
+
+  a = 0
+
+  /* Second: property access */
+  l\u0065t
+  [a] = [3]
+
+  assert(let[0][0] === 3)
+}
+f2()
+
+var arr = []
+
+for (let in ["x","y"])
+  arr.push(let)
+
+assert(arr[0] === "0")
+assert(arr[1] === "1")
+
+/* Let and arrow */
+
+for (let => 4; false ; ) ;
+
+let => 5
+
+/* Let label */
+let: break let