TOOLS-202 add oplog flag test
TOOLS-202 add asserts around toolTest.runTool calls in oplog flag test
TOOLS-202 add test for --dumpDbUsersAndRoles
TOOLS-202 add test for mongodump --repair
TOOLS-202 make --dumpDbUsersAndRoles test work with auth
TOOLS-202 enforce that mongodump --oplog fails fast on standalone and sharded
TOOLS-202 make --dumpDbUsersAndRoles test cover case where --db unspecified
TOOLS-202 add additional asserts and comments
TOOLS-202 add --excludeCollection test for mongodump
TOOLS-202 add mongodump --excludeCollectionsWithPrefix tests