Fixes how applied_bottomup_nonce is handled. Before there was a shared bottom_up nonces for the execution of every subnet, but sharing a nonce for all child subnets removes the separation between them and could lead to a subnet stalling the ability to exchange cross-net messages for all other child subnets. This improvement over the execution of cross-net messages fixes this problem.
A test to catch a bug that we fixed for which the committed previous checkpoint for a subnet was being modified before being persisted fixed in this PR: https://github.com/consensus-shipyard/ipc-actors/pull/89 This test should catch future regressions.
This PR includes:
applied_bottomup_nonceis handled. Before there was a shared bottom_up nonces for the execution of every subnet, but sharing a nonce for all child subnets removes the separation between them and could lead to a subnet stalling the ability to exchange cross-net messages for all other child subnets. This improvement over the execution of cross-net messages fixes this problem.