Except for nil literals, we don't want to look at the optional itself,
since the typechecker would implicitly look to the underlying type.
rdar://problem/24707210
If there is a type context, hide literal suggesetions that don't match
it, unless they are keywords and we have filtered to their names.
Incidentally fix an output buffering issue when combining filtering with
the -raw flag in complete-test.
Part of rdar://problem/23865118
In practice things that are float literal convertible are also integer
literal convertible so this isn't pulling its weight.
Part of rdar://problem/23865118
Go beyond the existing keyword completions to include more literal
suggestions: 0, 0.0, "text", [item], [key: value], (item, item)
For rdar://problem/21923069
Swift SVN r32890
