Ultra-slow JunitTest_sc_unoapi

[Stephan Bergmann]

FYI, at least with my recent master --enable-dbgutil builds (on Fedora 
18), JunitTest_sc_unoapi seemingly takes forever (but eventually does 
finish).  It looks like Java test code calls a ScCellRangeObj::doImport 
where that ScCellRangeObj's aRange.aEnd.nRow = 1048575 is pretty large, 
leading to ~endless ScDocument::Broadcast work.

Maybe related to some of Kohei's recent work on sc broadcasting?

Stephan