Gate nonce-overwrite change

[CriesofCarrots]

Problem

(From #11032)
As of #10973 , a successful nonce transaction advances the nonce to the most recent blockhash from the RecentBlockhashes sysvar instead of re-overwriting that nonce with the most recent bank blockhash. We expect those hashes to be the same, but in fact that can be different in the final tick of the slot, due to this:

solana/runtime/src/bank.rs

Line 1255 in 1880621

if self.is_block_boundary(current_tick_height + 1) {

This caused a bank hash mismatch on our api nodes.

We fixed the discrepancy, but that fix needs gating due to changing the bank. Therefore the overwrite also needs gating to avoid breaking anything while nodes are upgrading.

Summary of Changes

• Pass fix_recent_blockhashes_sysvar_delay into prepare_if_nonce_account() to gate overwrite in tandem with recent_blockhashes_sysvar_delay fix

[t-nelson]

Much less gross! 🎉

[codecov]

Codecov Report

Merging #11079 into v1.2 will increase coverage by 0.0%.
The diff coverage is 100.0%.

@@          Coverage Diff           @@
##            v1.2   #11079   +/-   ##
======================================
  Coverage   82.1%    82.1%           
======================================
  Files        309      309           
  Lines      72593    72597    +4     
======================================
+ Hits       59608    59632   +24     
+ Misses     12985    12965   -20