[rfc] Cleaning up .mod files from testsuite runs

[François-Xavier Coudert]

> How do people feel about this?  I can prepare a patch for the 
> other cases if people think it is worth doing.

There are lots of testcases using modules, and will certainly be more in the 
future. Couldn't we add a general mechanism to do this (question is, is 
there any case where we have a .mod file that we'd like to keep after a 
testcase is run)?

FX