bionic: linker: Load shim libs *before* the self-linked libs

bionic: linker: Load shim libs *before* the self-linked libs

By loading them earlier, this allows us to override a symbol in
a library that is being directly linked.

I believe this explains why some people have had problems shimming
one lib but when the changet he shim to be against a different
lib it magically works.

It also makes it possible to override some symbols that were
nearly impossible to override before this change.  For example, it is
pretty much impossible to override a symbol in libutils without
this change because it's loaded almost everywhere so no matter
where you try to place the shimming, it will be too late and
the other symbol will have priority.

In particularly, this is necessary to be able to correctly
shim the VectorImpl symbols for dlx.

Change-Id: I461ca416bc288e28035352da00fde5f34f8d9ffa