QLS: statically enable/disable fault injection depending on the SUT

[jorisdral]

Builds on top of #533.

This is a WIP, so not ready for review yet.

Faults can only be injected into a mocked HasFS, but not all the SUTs we test use a mocked HasFS. If the SUT does not make use of a mocked HasFS then the result of fault injection will always be InjectFaultAccidentalSuccess. This PR adds some boilerplate for statically enabling/disabling fault injection depending on the SUT.

Fault injection is then enabled for the following SUTs:

• The "real" implementation in IO using a mocked HasFS
• The "real" implementation in IOSim using a mocked HasFS

Fault injection is then disabled for the following SUTs:

• The reference implementation: it does not use a HasFS
• The "real" implementation in IO using the real HasFS: it uses the real file system