v2.0: SIMD-0118: fix total_rewards for recalculation (backport of #2780)

[mergify]

Problem

A node that reboots from a snapshot that was created during the partitioned epoch reward period may diverge from the cluster. This is because the total rewards value currently stashed in the EpochRewards sysvar and used to populate PointValue in recalculation is the total lamports to actually be distributed:

agave/runtime/src/bank/partitioned_epoch_rewards/calculation.rs

Line 180 in 7e6399a

total_rewards: validator_rewards_paid + total_stake_rewards_lamports,

agave/runtime/src/bank/partitioned_epoch_rewards/calculation.rs

Line 566 in fff6257

rewards: epoch_rewards_sysvar.total_rewards,

In the initial calculation, however, this part of the PointValue is the total lamports available to be split/distributed. In a cluster with a diverse collection of stake accounts (like testnet), the lamports actually distributed is likely to be less than what is available, due to rounding to whole lamports. Different PointValue::rewards values may yield different calculated rewards.

Summary of Changes

Populate EpochRewards::total_rewards from the calculated PointValue::rewards

---

This is an automatic backport of pull request #2780 done by [Mergify](https://mergify.com).

[mergify]

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Changes to be committed:
	modified:   programs/stake/src/stake_instruction.rs
	modified:   rpc/src/rpc.rs
	modified:   runtime/src/bank/partitioned_epoch_rewards/calculation.rs
	modified:   runtime/src/bank/partitioned_epoch_rewards/distribution.rs
	modified:   runtime/src/bank/partitioned_epoch_rewards/mod.rs
	modified:   runtime/src/bank/partitioned_epoch_rewards/sysvar.rs
	modified:   runtime/src/bank/sysvar_cache.rs
	modified:   sdk/program/src/epoch_rewards.rs

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   programs/bpf_loader/src/syscalls/mod.rs
	both modified:   sdk/src/feature_set.rs

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[mergify]

If this PR represents a change to the public RPC API:

1. Make sure it includes a complementary update to rpc-client/ (example)
2. Open a follow-up PR to update the JavaScript client @solana/web3.js (example)

Thank you for keeping the RPC clients in sync with the server API @mergify[bot].

[mergify]

The Firedancer team maintains a line-for-line reimplementation of the
native programs, and until native programs are moved to BPF, those
implementations must exactly match their Agave counterparts.
If this PR represents a change to a native program implementation (not
tests), please include a reviewer from the Firedancer team. And please
keep refactors to a minimum.

[CriesofCarrots]

This backport fixes a bug in partitioned epoch rewards that is currently affecting testnet; it is necessary for further rollout of the partitioned epoch rewards feature.