Add line layout performance test that exercises more cases

Add line layout performance test that exercises more cases
https://bugs.webkit.org/show_bug.cgi?id=124041

Reviewed by Anders Carlsson.

The existing line-layout.html covers the most basic left-aligned case only.
Add a test with more coverage for things that are mostly not yet supported by the simple
line layout path:

- centered text
- right aligned text
- justified text
- pre
- white-space:pre-wrap
- text with simple inlines
- text with br

* Layout/line-layout-simple.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@158920 268f45cc-cd09-0410-ab3c-d52691b4dbfc