Revert "solve circular reference problems with bsonparser which prevent gc"

This reverts commit 7759ce0c9b173c4b9b3cdaa8b8d8a7cfd4253eb6.
Revert "reset parseprocesslog instance on-demand, right before iterating it"

This reverts commit e9894cff46a1d1ed33ce7108174f36c71c36ade1.