Check program modification slots during cold start

[pgarg66]

Problem

During cold start, the program cache could have an incomplete view of the deployed/modified programs. The cache relies on program management instructions to update and manage program cache entries during regular run time. But, at the startup ledger may have modifications to the program that are not yet rooted (i.e. only valid on certain forks). This can lead to execution of an outdated program.

Summary of Changes

• Compute the highest slot in the startup/snapshot ledger
• Until the root slot moves past the highest slot, do the following
  • Read the program state to find the deployment slot.
  • If the deployment slot is in future compared to the program entry in the cache, treat the program as missing in the cache.
  • This will trigger the reloading of the program by reading the program account visible on the current slot.

Fixes #

[codecov]

Codecov Report

Merging #31331 (7ca824f) into master (2dcdfff) will increase coverage by 0.0%.
The diff coverage is 76.4%.

@@           Coverage Diff            @@
##           master   #31331    +/-   ##
========================================
  Coverage    81.5%    81.5%            
========================================
  Files         734      734            
  Lines      207153   207288   +135     
========================================
+ Hits       168955   169073   +118     
- Misses      38198    38215    +17     

[yihau]

#31348 has been merged. could you try to rebase again? thank you for your patient!