+(dir-rm-cwd) try to remove "/a"
+(dir-rm-cwd) remove failed
+(dir-rm-cwd) try to remove "../a" (must fail)
+(dir-rm-cwd) try to remove ".././a" (must fail)
+(dir-rm-cwd) try to remove "/./a" (must fail)
+(dir-rm-cwd) open "/a"
+(dir-rm-cwd) open "."
+(dir-rm-cwd) "/a" and "." must have same inumber
+(dir-rm-cwd) "/" and "/a" must have different inumbers
+(dir-rm-cwd) chdir "/a"
+(dir-rm-cwd) open "."
+(dir-rm-cwd) "." must have same inumber as before
+(dir-rm-cwd) chdir "/"
+(dir-rm-cwd) try to remove "a" (must fail: still open)
+(dir-rm-cwd) verify "/a" is empty