[GC] Fixed a memory leak introduced in r26379.  In particular, the consolidation of Parrot_forall_header_pools() meant that the non-const PMC pool was never swept or freed during global destruction.
[GC] Fixed a memory leak introduced in r26379.  In particular, the
consolidation of Parrot_forall_header_pools() meant that the non-const PMC pool
was never swept or freed during global destruction.

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@26585 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

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