Added a new field "origOff" to the SingleLocaleArithmeticArray class to store a precomputed combination of the off tuple and the orig value to reduce the number of fields accessed and the number of subtractions in an array access of non-stridable arrays.
Added a new field "origOff" to the SingleLocaleArithmeticArray class
to store a precomputed combination of the off tuple and the orig value
to reduce the number of fields accessed and the number of subtractions
in an array access of non-stridable arrays.

The performance impact is insignificant at least on test_for2d:

c -O3                             : 0.40
chpl before -O3 --no-bounds-checks: 1.20
chpl after  -O3 --no-bounds-checks: 1.19


git-svn-id: 88467cb1fb04b8a755be7e1ee1026be4190196ef@9581 3a8e244f-b0f2-452b-bcba-4c88e055c3ca

chizarlicious/chapel,hildeth/chapel,sungeunchoi/chapel,hildeth/chapel,chizarlicious/chapel,chizarlicious/chapel,hildeth/chapel,CoryMcCartan/chapel,hildeth/chapel,chizarlicious/chapel,CoryMcCartan/chapel,sungeunchoi/chapel,sungeunchoi/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,hildeth/chapel,hildeth/chapel,sungeunchoi/chapel,CoryMcCartan/chapel,chizarlicious/chapel,chizarlicious/chapel,sungeunchoi/chapel,CoryMcCartan/chapel,sungeunchoi/chapel,sungeunchoi/chapel,CoryMcCartan/chapel,chizarlicious/chapel,sungeunchoi/chapel,hildeth/chapel