Remove tests

[fhenneke]

This PR removes tests.

There have been problems with long delays in EBBO tests. This is probably due to the number of tests run and their efficiency. To see where the issues are coming from and for general clean up, some tests are removed from the daemon.

• Reference solver surplus test: does not work at the moment.
• Buffer monitoring test: not related to EBBO and seems to slow down the loop significantly
• CoW AMM commitment test: obsolete with the new version of CoW AMMs

For now the code for tests is not removed completely as they can still be run manually. Longterm, all of the code should be removed as well.

[harisang]

Makes sense!