Make QQmlExpression more robust when initializing from script string
Make QQmlExpression more robust when initializing from script string

Don't require a binding id to initialize the url/col/line. Fixes
tst_qqmlexpression with the new compiler code path, where the id isn't needed.

Change-Id: Ic09d850038c93fdc4f2bee6190cb515081dd5865
Reviewed-by: Lars Knoll <a812617a4072dcbeb80684eca0f369f0083af109@digia.com>

qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,qmlc/qtdeclarative,mgrunditz/qtdeclarative-2d,mgrunditz/qtdeclarative-2d,qmlc/qtdeclarative