Fixes for the incremental analysis with cfg comparison

[stilscher]

This PR arises from several incremental test cases that failed when enabling the cfg comparison (#835). With the grouping of globals (#836) and the bug fix in 6f2486a a couple of problems were fixed but resulted in more/different test cases failing.

This PR includes:

• fix reluctant destabilization: return nodes of partially changed functions need to be collected for reluctant destabilization (not only when reluctant is turned off!)
• extended update_suite.rb with the option -c to run incremental tests with cfg comparison
• run update_suite.rb -c regularly with regression tests

It remains to do:

• the incremental test 11/15 mutex-simple-wrap1 still fails with cfg comparison because an expected race is not found. It seems that the restarting differs from the run with the ast comparison, but it needs to be investigated further what the actual issue is.
  Update: The reason seems to be that fuel is lost when destabilizing through side_dep first before destabilizing through infl. I suggest to change the behaviour of the destabilize_with_sides in Avoid cyclic destabilize in destabilize_with_sides leading to less fuel than expected #862.

Closes #835

[jerhard]

Looks good!

[sim642]

Is there a reason this is to be merged into #836 instead of master? I just merged master into this to confirm that #862 fixes the test, not realizing it's not against master. This made the diff really ugly here, so if there was a reason for this, I'll hard reset this branch back before my merge.

[stilscher]

The only reason was that I needed #836 to see which tests are actually failing when grouping the globals correctly. I am not sure whether it's now best to wait for #836 to be completed (it should be already, but the cil fix for c99 inlines is still missing) or merge this into master directly.

[sim642]

I tried to see how it looks like rebased for master, but it gets overly messy and the CFG testing added here due to #836. So I reset it back and lets wait for #836.