Properly handle primitive arguments in Object methods (#3342)

ES2015 allows primitive arguments for most of the Object built-ins.
This change implements handling for these arguments in affected methods.

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

tests/jerry/object-keys.js

@@ -61,14 +61,6 @@ assert (props.indexOf("prop") !== -1);
 assert (props.indexOf("method") !== -1);
 assert (props.length === 2);
 
-// Test non-object argument
-try {
-  Object.keys("hello");
-  assert (false);
-} catch (e) {
-  assert (e instanceof TypeError);
-}
-
 var o = {};
 
 Object.defineProperty(o, 'a', {