gitserver: Always use Commits in HasCommitAfter

[eseliger]

There used to be two implementations of this, one for with subrepo enabled, one for without. This PR aligns those two to both use the Commits method.
One code path less, and one API less that we need to port to gRPC.

Test plan:

Existing unit tests are still passing.

[eseliger]

• gitserver: Deprecate Exec and remove localGit #62773 : 3 dependent PRs (#62774 , #62801 , #62825 )
• gitserver: Remove and deprecate no_timeout option from exec #62743
• rockskip: Replace second long-running process with gRPC API #62734
• gitserver: Add CommitLog API to replace client-side Commits #62606
• gitserver: Fix duration reported for ChangedFiles #62603
• gitserver: Make ReadDir return an iterator on client side #62602
• gitserver: Move implementation of HasCommitAfter to caller #62520
• gitserver: Always use Commits in HasCommitAfter #62519 👈
• gitserver: Implement CommitLog using Commits #62518
• gitserver: Move CommitsUniqueToBranch to callsite #62514
• gitserver: Implement CommitsUniqueToBranch using Commits #62513
• gitserver: Implement Stat and ReadDir in gRPC API #62107
• main

This stack of pull requests is managed by Graphite. Learn more about stacking.

Join @eseliger and the rest of your teammates on Graphite

[eseliger]

Merge activity

• May 10, 7:24 PM EDT: Graphite rebased this pull request as part of a merge.
• May 10, 7:29 PM EDT: @eseliger merged this pull request with Graphite.