Block completion list on import declaration name and fix the crash in sy...

...mbol display name when import declaration is incomplete

Fixes #991
They are not two cases... They are both same cases when either import /*completion here*/q =  or import /*completion here*/q = a. I updated this to add another one when there is no name specified. I like that this is in one place where we are testing completion list of name of import statement with different states import declaration could be