Bug in the pageHeights function

[Paul Dupuis]

I don't know how many people have old fashion printing in their apps (I
know, printing is so 20th century!). I wanted to let anyone out there
using the pageHeights function that there is a bug in pageHeights from
LC6.7.x through LC9.0.0 that returns really wacky numbers for certain
content of the field the pageHeights is being computed for.

For the exact same field, no change in properties, just changing teh
content by setting the htmlText, different content will generate
abnormal pageHeights numbers. For example

For LC9.0.0, the pageHeights reports
692
689
-51061

For LC6.7.11, the pageHeights reports
667
666
4294919018

Correct values are returned under LC6.6.5. It took use a long time to
track this down because it does appear to be content based! So, just in
case any others have been experiencing very weird random printing issue,
I wanted to let folks know.

See https://quality.livecode.com/show_bug.cgi?id=21491