Figure out why table32-span-* are wrong.

Add testcases based on:
  http://dbaron.org/css/test/2004/intrinsic/column-width-border-spacing
  http://dbaron.org/css/test/2004/intrinsic/float-intrinsic
  http://dbaron.org/css/test/2004/intrinsic/table-fix-percent-minwidth-increase
  http://dbaron.org/css/test/2004/intrinsic/table-nonoptimal
Do better testcases of:
  percentage and auto widths for blocks, floats, and tables
  min-width and max-width, for blocks, floats, and tables