Fix IE issues: noPostMessageApply test ; target origin for empty iframes

Improve the hack for testing IE9+ subwindows via /Trident/.

Improve the check about validity of protocol and host name while computing the
target origin of an iframe (it fixes a not working parent2iframe
communication in IE, while the parent is calling singalReady() and the
iframe reports neither a protocol nor host infromation via urlHack) .