test-from-egg and test-from-prefixdir are sometimes not testing the right code

[davidsarah]

There is currently nothing to ensure that the test-from-egg and test-from-prefixdir steps of pycryptopp builds aren't subject to the same bug as ​http://tahoe-lafs.org/trac/tahoe-lafs/ticket/1137 .

Fixing this probably just requires updating misc/build_helpers/run_trial.py to reflect ​http://tahoe-lafs.org/trac/tahoe-lafs/browser/misc/build_helpers/run_trial.py (which I believe is already generic enough to handle the pycryptopp build setup).

This would allow detecting failures like ​this one, rather than silently testing the wrong code. (I don't have specific evidence that the current pycryptopp builders are testing the wrong code, but we didn't know that the Tahoe-LAFS builders were until recently.)

[davidsarah]

Test fix applied in [719].

We were indeed testing the wrong code on the 'zomp' builder:

• ​http://tahoe-lafs.org/buildbot-pycryptopp/builders/Zooko%20zomp%20Mac-amd64%2010.6%20py2.6/builds/11/steps/test-from-egg/logs/stdio
• ​http://tahoe-lafs.org/buildbot-pycryptopp/builders/Zooko%20zomp%20Mac-amd64%2010.6%20py2.6/builds/11/steps/test-from-prefixdir/logs/stdio

[davidsarah]

and on the kyle-openbsd-amd64 and randy-freebsd-amd64 builders.

[zooko]

We've removed the test-from-egg and test-from-prefixdir tests.