Skip BCL-timezone-related test on Mono.
Skip BCL-timezone-related test on Mono.

nodatime/nodatime,nodatime/nodatime,malcolmr/nodatime,zaccharles/nodatime,zaccharles/nodatime,BenJenkinson/nodatime,jskeet/nodatime,malcolmr/nodatime,zaccharles/nodatime,jskeet/nodatime,malcolmr/nodatime,malcolmr/nodatime,zaccharles/nodatime,zaccharles/nodatime,zaccharles/nodatime,BenJenkinson/nodatime