In order to make the flamegraphs easier to consume by humans, we change
the profiler output in the following ways:

1. Don't print package ids anymore. They are not particularly useful
   but cause a lot of noise.
2. Remove a few useless angle bracket and move the printed names of
   DAML-LF closer to their surface level names.
3. Unmangle identifiers on a best effort basis.
4. Give the profiles shorter names such that they don't occupy the
   whole screen and leave some space for the navigation buttons of the
   Speedscope UI.

CHANGELOG_BEGIN
CHANGELOG_END

Pull Request Checklist

• Read and understand the contribution guidelines
• Include appropriate tests
• Set a descriptive title and thorough description
• Add a reference to the issue this PR will solve, if appropriate
• Include changelog additions in one or more commit message bodies between the CHANGELOG_BEGIN and CHANGELOG_END tags
• Normal production system change, include purpose of change in description

NOTE: CI is not automatically run on non-members pull-requests for security
reasons. The reviewer will have to comment with /AzurePipelines run to
trigger the build.

This is part of #6199.

This change is