Pass forceClose "true" to SkPath::Iter constructor in

Pass forceClose "true" to SkPath::Iter constructor in
GrPathUtils::worstCasePointCount().  worstCasePointCount() is sometimes
returning a lower value than the number of points subsequently generated by
the path renderers.  This is because it constructs the SkPath::Iter with
forceClose set to "false", while the path renderers use one with forceClose
set to "true".  They should both be the same, and since we're filling paths, I
think it should be set "true".

Review URL:  http://codereview.appspot.com/4552047/

git-svn-id: http://skia.googlecode.com/svn/trunk@1353 2bbb7eff-a529-9590-31e7-b0007b416f81