Suggestions in the member selection expression shouldn't contain the constructor

[ShinyaYoshida]

Hi Jan,
In the member selection expression, REPL shouldn't print the constructor as
suggestion:

-> "".[TAB]
CASE_INSENSITIVE_ORDER String( <- INVALID SUGGESTION charAt( etc...

Please review my fix & test with small refactoring:
(If you don't like my refactoring, please omit it)
http://cr.openjdk.java.net/~shinyafox/kulla/201504231/webrev.00/

Regards,
shinyafox(Shinya Yoshida)