Reverted bshrub-in-mdir assert in lfsr_mdir_commit epilogue

Unfortunately, even with the mdir update order fixed, this assert still
ends up violated by lfsr_rename.

But only if lfsr_rename brings along open + unsynced shrubs.

The problem is we copy these shrubs over with LFSR_TAG_MOVE, but don't
update the related mdir until the epilogue in lfsr_rename. This avoids
needing to parse LFSR_TAG_MOVE tags in the epilogue in lfsr_mdir_commit,
but does mean we can't rely on this assert.

Oh well, we at least have the bshrub-in-mdir assert in
lfsr_mdir_commit's prologue. This at least gives us confidence that this
constraint is usually held, even if it makes debugging a pain-in-the-
ass.

Found by our test_forphans_mv test, which is working as intended.

No code changes.

lfs.c

@@ -8687,11 +8687,6 @@ static int lfsr_mdir_commit(lfs_t *lfs, lfsr_mdir_t *mdir,
     // update any staged bshrubs
     for (lfsr_omdir_t *o = lfs->omdirs; o; o = o->next) {
         if (lfsr_o_isbshrub(o->flags)) {
-            // a bshrub outside of its mdir means something has gone
-            // horribly wrong
-            LFS_ASSERT(!lfsr_bshrub_isbshrub(&((lfsr_obshrub_t*)o)->bshrub_)
-                    || ((lfsr_obshrub_t*)o)->bshrub_.u.bshrub.blocks[0]
-                        == o->mdir.rbyd.blocks[0]);
             ((lfsr_obshrub_t*)o)->bshrub = ((lfsr_obshrub_t*)o)->bshrub_;
         }
     }