icasefs: avoid normcase()-ing in util.fspath() for efficiency...
icasefs: avoid normcase()-ing in util.fspath() for efficiency
'dirstate._normalize()', the only caller of 'util.fspath()', has
already normcase()-ed path before invocation of it.
normcase()-ed root can be cached on dirstate side, too.
so, this patch changes 'util.fspath()' API specification to avoid
normcase()-ing in it.
