Scanner rework. (#3038)

The scanner was an on-demand tool of the parser, which was triggered by certain
statements. After the rework, the scanner runs only once, and collects all information.
This information is passed to the parser.

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

tests/jerry/es2015/arrow-function.js

@@ -125,6 +125,13 @@ default:
   func = () =>
     ((([0,0,0])))
   assert (func ().length == 3);
+
+  func = (a = 5, b = 7 * 2) => a + b;
+  assert (func() == 19);
+  assert (func(1) == 15);
+
+  func = (a = Math.cos(0)) => a;
+  assert (func() == 1);
 }
 
 must_throw ("var x => x;");
@@ -136,6 +143,7 @@ must_throw ("(x,y,) => 0");
 must_throw ("x\n => 0");
 must_throw ("this => 0");
 must_throw ("(true) => 0");
+must_throw ("()\n=>5");
 must_throw_strict ("(package) => 0");
 must_throw_strict ("(package) => { return 5 }");
 must_throw_strict ("(x,x,x) => 0");