Fixed test out-of-space issues with powerloss testing

These are just incorrect limits in the tests that can be triggered by
powerloss testing, which can end up with more metadata-pairs than
without powerloss testing due to orphans.

tests/test_dirs.toml

@@ -179,6 +179,7 @@ code = '''
 
 [cases.test_dirs_many_reentrant]
 defines.N = [5, 11]
+if = 'BLOCK_COUNT >= 4*N'
 reentrant = true
 code = '''
     lfs_t lfs;