bdlcc_deque.t.cpp: isolate exception-testing of pops to single-threaded in TC 6
bdlcc_deque.t.cpp: isolate exception-testing of pops to single-threaded in TC 6

bloomberg/bde,bloomberg/bde,che2/bde,che2/bde,che2/bde,bloomberg/bde,bloomberg/bde,che2/bde,bloomberg/bde