Remove sane.c:chk_idcache()
Remove sane.c:chk_idcache()

Creating a test idcache lock caused the walkdir()
in sfiles to hit an assertion on MacOS when files
are created and deleted during the readdir.

bk: 46df1788aTV51Iab5fErH8n98W7CvQ
bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper,bitkeeper-scm/bitkeeper