Add handling for RegExp unicode and sticky flags (#3341)

JerryScript-DCO-1.0-Signed-off-by: Dániel Bátyai dbatyai@inf.u-szeged.hu

tests/jerry/es2015/regexp-construct.js

@@ -28,3 +28,24 @@ try {
 } catch (e) {
   assert(e === 5);
 }
+
+r = new RegExp ("a","gimuy");
+assert (r.global === true);
+assert (r.ignoreCase === true);
+assert (r.multiline === true);
+assert (r.unicode === true);
+assert (r.sticky === true);
+
+try {
+  new RegExp ("a", "uu");
+  assert (false);
+} catch (e) {
+  assert (e instanceof SyntaxError);
+}
+
+try {
+  new RegExp ("a", "yy");
+  assert (false);
+} catch (e) {
+  assert (e instanceof SyntaxError);
+}