v1.18: Fix: deploy program on last slot of epoch during environment change (backport of #101)

[mergify]

Problem

On runtime environment change, the program deployed in the last slot of the prior epoch will use incorrect environment. This will also prevent the loading of the program in future epochs with the correct runtime environment.

Summary of Changes

The problem happens because the effective slot for the deployed program is in the next epoch, where the new environment becomes effective.
This change updates the program deployment procedure, to use the environment of the epoch where the program actually becomes effective.

Fixes #

---

This is an automatic backport of pull request #101 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 91b1ee3 has failed:

On branch mergify/bp/v1.18/pr-101
Your branch is up to date with 'origin/v1.18'.

You are currently cherry-picking commit 91b1ee3df6.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   program-runtime/src/invoke_context.rs
	modified:   program-runtime/src/loaded_programs.rs
	modified:   programs/bpf_loader/src/lib.rs
	modified:   programs/bpf_loader/src/syscalls/mod.rs
	modified:   programs/loader-v4/src/lib.rs
	modified:   runtime/src/bank.rs

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   ledger-tool/src/program.rs
	both modified:   runtime/src/bank/tests.rs
	deleted by us:   svm/src/transaction_processor.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

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 89.83957% with 19 lines in your changes are missing coverage. Please review.

Project coverage is 81.6%. Comparing base (f0cd4e5) to head (9012ccd).

Additional details and impacted files

@@           Coverage Diff            @@
##            v1.18     #387    +/-   ##
========================================
  Coverage    81.5%    81.6%            
========================================
  Files         827      827            
  Lines      224453   224590   +137     
========================================
+ Hits       183132   183292   +160     
+ Misses      41321    41298    -23     

[willhickey]

Approved for backport to beta