table_remove: reduce temporary memory usage
table_remove: reduce temporary memory usage

The previous implementation can't close implicitly opened objects. For
example, if we open a column, its table is also opened implicitly. The
previous implementation can't close the table.

The new implementation can close implicitly opened objects. It reduces
memory usage for temporary opened objects including implicitly opened
objects.

It's enabled when the number of max threads is 0.

cosmo0920/groonga,naoa/groonga,kenhys/groonga,kenhys/groonga,naoa/groonga,naoa/groonga,groonga/groonga,komainu8/groonga,komainu8/groonga,naoa/groonga,kenhys/groonga,naoa/groonga,kenhys/groonga,kenhys/groonga,komainu8/groonga,cosmo0920/groonga,groonga/groonga,groonga/groonga,naoa/groonga,groonga/groonga,groonga/groonga,groonga/groonga,naoa/groonga,groonga/groonga,komainu8/groonga,cosmo0920/groonga,naoa/groonga,komainu8/groonga,cosmo0920/groonga,kenhys/groonga,komainu8/groonga,komainu8/groonga,groonga/groonga,cosmo0920/groonga,kenhys/groonga,cosmo0920/groonga,cosmo0920/groonga,kenhys/groonga,cosmo0920/groonga,komainu8/groonga