fusefs: Fix a bug during VOP_STRATEGY when the server changes file size

fusefs: Fix a bug during VOP_STRATEGY when the server changes file size

If the FUSE server tells the kernel that a file's size has changed, then
the kernel must invalidate any portion of that file in cache.  But the
kernel can't do that during VOP_STRATEGY, because the file's buffers are
already locked.  Instead, proceed with the write.

PR:		256937
Reported by:	Agata <chogata@moosefs.pro>
Tested by:	Agata <chogata@moosefs.pro>
MFC after:	2 weeks
Reviewed by:	pfg
Differential Revision: https://reviews.freebsd.org/D32332