[CSS Exclusions] Implement text alignment for shape-inside
https://bugs.webkit.org/show_bug.cgi?id=101086

Reviewed by Alexandru Chiculita.

Adding tests to make sure that shape-inside layout correctly supports
the different values of text-align.

* fast/exclusions/resources/multi-segment-polygon.js:
(createOrInsert):
* fast/exclusions/shape-inside/shape-inside-text-align-expected.html: Added.
* fast/exclusions/shape-inside/shape-inside-text-align.html: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@151650 268f45cc-cd09-0410-ab3c-d52691b4dbfc