* Persist EpochRewards sysvar between reward intervals
* Adjust initial EpochRewards balance to ensure it is not debited out of existence
* Set EpochRewards::active = false at end of distribution
* Fix tests
* Extend test to 2 epochs, assert sysvar still exists
* Stop adjusting EpochRewards balance based on rewards
* Fix tests
* Review suggestions
* Add epoch rewards sysvar test to program test
* Add a test to check epoch rewards sysvar inside/outisde reward interval
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Co-authored-by: HaoranYi <haoran.yi@solana.com>
Tyera
HaoranYi
Jack May