path ops -- handle non-finite numbers

Op() and Simplify() do nothing if the input
is non-finite. Add code and tests.
Review URL: https://codereview.chromium.org/14407006

git-svn-id: http://skia.googlecode.com/svn/trunk/include@8882 2bbb7eff-a529-9590-31e7-b0007b416f81
1 file changed