fsmonitor: layer on another hack in bser.c for os.stat() compat (issue5811)
It's unclear to me how these `bserobj_tuple` objects are used, other
than as stat objects. This should fix fsmonitor in the wake of
ffa3026d4196 and similar changes. I regret the hack here, but the code
already has plenty of hg-specific hacks. :(
It feels like we should be able to use int(result.st_mtime) globally,
but that doesn't work. See issue4836 for a bug that was hard to track
down relating to rounding behavior causing very subtle dirstate
problems.
Differential Revision: https://phab.mercurial-scm.org/D2939