inject a 32767 bounded cliprect before using SuperSampler blitter, to avoid

inject a 32767 bounded cliprect before using SuperSampler blitter, to avoid
crash/assert when our run-array is larger than int16_t. Better fix may be to
"tile" the drawing, so we never see a clip that's too wide, and perhaps this
technique can help us avoid disabling AA for large parths (not sure tho).

git-svn-id: http://skia.googlecode.com/svn/trunk@3104 2bbb7eff-a529-9590-31e7-b0007b416f81