Revert "Globally disable threading for these for now."

This effctively reverts commit d677bf45.

It appears that the memory corruption was an out-of-memory
condition on 32bit Windows, so restore XclExpRow threading for now.

Change-Id: I85e61e5850bd8ff3288dac39de7699cd05dd4de8

sc/source/filter/excel/xetable.cxx

@@ -2065,7 +2065,7 @@ void XclExpRowBuffer::Finalize( XclExpDefaultRowData& rDefRowData, const ScfUInt
 
     GetProgressBar().ActivateFinalRowsSegment();
 
-#if 0
+#if 1
     // This is staggeringly slow, and each element operates only
     // on its own data.
     const size_t nRows = maRowMap.size();