(Closes #3155) Optimise InlineTrans so that it only copies target Routine

[arporter]

Previously, it copied the whole Container and that got very expensive for large pieces of code. We weren't actually making use of the fact that we had the whole Container so I've just changed what the transformation copies.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.90%. Comparing base (a3df94c) to head (90de7ad).
⚠️ Report is 6 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3161   +/-   ##
=======================================
  Coverage   99.90%   99.90%           
=======================================
  Files         376      376           
  Lines       52887    52886    -1     
=======================================
- Hits        52835    52834    -1     
  Misses         52       52           

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[sergisiso]

This looks great @arporter I will bring it to master and do an integration test to be extra safe before the release.