Corrected 'DecimalImpUtil' arithmetic test cases.
Corrected 'DecimalImpUtil' arithmetic test cases.

Test cases were expanded to use 'LOOPX_ASSERT' macros to indicate
expression-argument values.  Equality expressions were adapted to
a testing function 'nanEqual' which treats 'NaN' states as a value
state, not an invalid state.  Some documentation and comments in
the test driver were corrected, as well.

osubboo/bde,bloomberg/bde-allocator-benchmarks,osubboo/bde,RMGiroux/bde-allocator-benchmarks,che2/bde,abeels/bde,saxena84/bde,RMGiroux/bde-allocator-benchmarks,bowlofstew/bde,dbremner/bde,jmptrader/bde,apaprocki/bde,saxena84/bde,RMGiroux/bde-allocator-benchmarks,bloomberg/bde,saxena84/bde,saxena84/bde,gbleaney/Allocator-Benchmarks,minhlongdo/bde,apaprocki/bde,abeels/bde,che2/bde,apaprocki/bde,dharesign/bde,idispatch/bde,minhlongdo/bde,minhlongdo/bde,abeels/bde,osubboo/bde,osubboo/bde,frutiger/bde,bowlofstew/bde,apaprocki/bde,bloomberg/bde,abeels/bde,frutiger/bde,mversche/bde,mversche/bde,che2/bde,abeels/bde,apaprocki/bde,bloomberg/bde-allocator-benchmarks,gbleaney/Allocator-Benchmarks,gbleaney/Allocator-Benchmarks,dharesign/bde,che2/bde,frutiger/bde,minhlongdo/bde,mversche/bde,jmptrader/bde,RMGiroux/bde-allocator-benchmarks,bloomberg/bde-allocator-benchmarks,frutiger/bde,gbleaney/Allocator-Benchmarks,bloomberg/bde-allocator-benchmarks,bowlofstew/bde,dbremner/bde,dharesign/bde,bloomberg/bde,dbremner/bde,dbremner/bde,mversche/bde,RMGiroux/bde-allocator-benchmarks,bowlofstew/bde,bloomberg/bde-allocator-benchmarks,idispatch/bde,bloomberg/bde,jmptrader/bde,dharesign/bde,jmptrader/bde,idispatch/bde,abeels/bde,idispatch/bde,bloomberg/bde