Avoid error messages during global GC.
Avoid error messages during global GC.


Former-commit-id: c9feb64258792079e06b401b0104516d10f68bc2 [formerly c9feb64258792079e06b401b0104516d10f68bc2 [formerly fabcc6a877ba912d0fbcc0432b71ff94e4fe05e3]]
Former-commit-id: 01683719a911d582e5def095aa1df41d2ed44de8
Former-commit-id: c0910559cdc6eda5bdbfa4ed747cf7ec208e70e7
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine