[lto][patch] Clear binfo

[Rafael Espindola]

The attached patch fixes the contained testcase. It also introduces a
regression:

g++.dg/opt/devirt1.C

Without the binfo we are unable to devirtualize the call. At this
point in the development of lto I think that trading a performance
regression for an ICE fix is a good choice. Once we have lto fully
working we can start looking at exactly what we want to put on disk to
implement this optimization again.

Cheers,
-- 
Rafael Avila de Espindola

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