altstack: Don't log internal calls in test cases

altstack/test/run.c uses some hairy macros to intercept the standard
library functions that altstack uses.  This has two purposes: 1) to
conditionally cause those functions to fail, and thereby test altstack's
error paths, and 2) log which of the library functions was called in each
testcase.

The second function isn't actually useful - for the purposes of testing the
module, we want to check the actual behaviour, not what calls it made in
what order to accomplish it.  Explicitly checking the calls makes it much
harder to change altstack's implementation without breaking the tests.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>