refactor: convertToIrrev speedup

[edkerk]

Main improvements in this PR:

• refactor:
  • convertToIrrev when converting all reactions to irreversible. This reduces running time of solveLP(model,1) by ~50% on a yeast model.

I hereby confirm that I have:

• Tested my code on my own machine
• Followed the development guidelines.
• Selected devel as a target branch
• If needed, asked first in the Gitter chat room about this PR

[github-actions]

This PR has been automatically tested with GH Actions. Here is the output of the tests:

 Running blastPlusTests . Done blastPlusTests Running cdhitTests . Done cdhitTests Running diamondTests . Done diamondTests Running hmmerTests . Done hmmerTests Running mafftTests . Done mafftTests Running sortIdentifiers_and_permuteModelTests . Done sortIdentifiers_and_permuteModelTests Running tinitTests . Done tinitTests

Note: In the case of multiple test runs, this post will be edited.