Show SuggestionsPopup when there is a misspelled span.

Due to I20a86c1bdeb361686, SuggestionsPopup was not shown when there
is a suggestion span that has misspelled flag and doesn't has any
suggestions. This CL makes SuggestionHelper#getSuggestionInfo return
misspelled span info separately.

Bug: 27534987

Change-Id: Ib76588f9388287a04f1f6c9d9067ae439e493a95