Reduce the max texture size to 8192x8192 and 256MB.
Reduce the max texture size to 8192x8192 and 256MB.

Seems to reduce jank and crashes.

servo/webrender,servo/webrender,alanamramjit/webrender,alanamramjit/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender