Fix table column widths after page break (#2502)
Fix table column widths after page break (#2502)

Node attributes are always string, so when a table was laid out, and
then a page break occurred before the table at a later point, `$colspan`
and `$rowspan` would always be string values and fail the checks below,
most notably the check where the minimum column width is set, so that
all columns received `0` minimum width.

Fixes #2395
dompdf/dompdf,dompdf/dompdf