GitLab

Courgette's algorithm allow removal for underused labels. However, this
was only used by ARM, whose support is recently removed. This CL is a
follow-up to remove more dead code.

* Remove AssemblyProgram::TrimLabels()
* Remove LabelManager::RemoveUnderusedLabels() and usage in test.

Bug: 1012592
Change-Id: Ia50ee2ec9f90e35ce123463e06edc9bfb5a868af
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1987863Reviewed-by: Etienne Pierre-Doray <etiennep@chromium.org>
Commit-Queue: Samuel Huang <huangs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#728682}