Do not run symbol lookup on already visited soinfos
Not taking into account already visited libraries
dramatically slows down dlsym in cases when there
are multiple occurrences of a large library in
dependency tree.
Bug: 16977077
(cherry picked from commit 042426ba6375f5c145379e598486ec6d675533c9)
Change-Id: I69d59e395e8112f119343e8a4d72fe31cd449f31